SELECT 
  cscart_products_categories.product_id, 
  GROUP_CONCAT(
    IF(
      cscart_products_categories.link_type = "M", 
      CONCAT(
        cscart_products_categories.category_id, 
        "M"
      ), 
      cscart_products_categories.category_id
    )
  ) AS category_ids, 
  product_position_source.position AS position 
FROM 
  cscart_products_categories 
  INNER JOIN cscart_categories ON cscart_categories.category_id = cscart_products_categories.category_id 
  AND cscart_categories.storefront_id IN (0, 1) 
  AND (
    cscart_categories.usergroup_ids = '' 
    OR FIND_IN_SET(
      0, cscart_categories.usergroup_ids
    ) 
    OR FIND_IN_SET(
      1, cscart_categories.usergroup_ids
    )
  ) 
  AND cscart_categories.status IN ('A', 'H') 
  LEFT JOIN cscart_products_categories AS product_position_source ON cscart_products_categories.product_id = product_position_source.product_id 
  AND product_position_source.category_id = 166 
WHERE 
  cscart_products_categories.product_id IN (
    76, 56, 57, 30, 246, 208, 173, 229, 211, 
    210, 209, 67, 25, 213, 215, 226, 154, 
    53, 52, 228, 161, 165, 166, 86, 106, 105, 
    247, 101, 33, 32, 163, 244, 212, 155, 
    55, 69, 206, 184, 183, 133, 132, 125, 
    120, 223, 225, 224, 146, 147
  ) 
GROUP BY 
  cscart_products_categories.product_id

Query time 0.00115

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "33.33"
    },
    "grouping_operation": {
      "using_temporary_table": true,
      "using_filesort": true,
      "cost_info": {
        "sort_cost": "1.39"
      },
      "nested_loop": [
        {
          "table": {
            "table_name": "cscart_categories",
            "access_type": "ALL",
            "possible_keys": [
              "PRIMARY",
              "c_status",
              "p_category_id"
            ],
            "rows_examined_per_scan": 83,
            "rows_produced_per_join": 3,
            "filtered": "4.00",
            "cost_info": {
              "read_cost": "19.42",
              "eval_cost": "0.66",
              "prefix_cost": "20.08",
              "data_read_per_join": "8K"
            },
            "used_columns": [
              "category_id",
              "storefront_id",
              "usergroup_ids",
              "status"
            ],
            "attached_condition": "((`atulecarter_atul_demo5`.`cscart_categories`.`storefront_id` in (0,1)) and ((`atulecarter_atul_demo5`.`cscart_categories`.`usergroup_ids` = '') or find_in_set(0,`atulecarter_atul_demo5`.`cscart_categories`.`usergroup_ids`) or find_in_set(1,`atulecarter_atul_demo5`.`cscart_categories`.`usergroup_ids`)) and (`atulecarter_atul_demo5`.`cscart_categories`.`status` in ('A','H')))"
          }
        },
        {
          "table": {
            "table_name": "cscart_products_categories",
            "access_type": "ref",
            "possible_keys": [
              "PRIMARY",
              "pt"
            ],
            "key": "PRIMARY",
            "used_key_parts": [
              "category_id"
            ],
            "key_length": "3",
            "ref": [
              "atulecarter_atul_demo5.cscart_categories.category_id"
            ],
            "rows_examined_per_scan": 2,
            "rows_produced_per_join": 1,
            "filtered": "20.97",
            "index_condition": "(`atulecarter_atul_demo5`.`cscart_products_categories`.`product_id` in (76,56,57,30,246,208,173,229,211,210,209,67,25,213,215,226,154,53,52,228,161,165,166,86,106,105,247,101,33,32,163,244,212,155,55,69,206,184,183,133,132,125,120,223,225,224,146,147))",
            "cost_info": {
              "read_cost": "8.86",
              "eval_cost": "0.28",
              "prefix_cost": "30.27",
              "data_read_per_join": "22"
            },
            "used_columns": [
              "product_id",
              "category_id",
              "link_type"
            ]
          }
        },
        {
          "table": {
            "table_name": "product_position_source",
            "access_type": "eq_ref",
            "possible_keys": [
              "PRIMARY",
              "pt"
            ],
            "key": "PRIMARY",
            "used_key_parts": [
              "category_id",
              "product_id"
            ],
            "key_length": "6",
            "ref": [
              "const",
              "atulecarter_atul_demo5.cscart_products_categories.product_id"
            ],
            "rows_examined_per_scan": 1,
            "rows_produced_per_join": 1,
            "filtered": "100.00",
            "cost_info": {
              "read_cost": "1.39",
              "eval_cost": "0.28",
              "prefix_cost": "31.94",
              "data_read_per_join": "22"
            },
            "used_columns": [
              "product_id",
              "category_id",
              "position"
            ]
          }
        }
      ]
    }
  }
}

Result

product_id category_ids position
25 195M
30 176M
32 176M
33 176M
52 202M
53 202M
55 187M
56 187M
57 187M
67 236M
69 236M
76 240M
86 238M
101 238M
105 238M
106 238M
120 237M
125 237M
132 182M,179
133 182,179M
146 179M
147 179M
154 181M
155 181M
161 198M,199
163 198M,199
165 199,198M
166 199,198M
173 199M
183 200M
184 200M
206 171M
208 171M
209 172M
210 172M
211 172M
212 172M
213 201M
215 201M
223 165M
224 165M
225 165M
226 201M
228 170M
229 170M
244 168M
246 199M
247 165M