SELECT 
  f.feature_id, 
  f.purpose, 
  p.product_id, 
  p.parent_product_id, 
  g.id, 
  g.code 
FROM 
  cscart_product_variation_group_features AS f 
  INNER JOIN cscart_product_variation_groups AS g ON f.group_id = g.id 
  INNER JOIN cscart_product_variation_group_products AS p ON f.group_id = p.group_id 
WHERE 
  p.product_id IN (150, 148, 149, 5, 372, 23, 350, 8)

Query time 0.00046

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "12.88"
    },
    "nested_loop": [
      {
        "table": {
          "table_name": "f",
          "access_type": "ALL",
          "possible_keys": [
            "idx_group_id"
          ],
          "rows_examined_per_scan": 3,
          "rows_produced_per_join": 3,
          "filtered": "100.00",
          "cost_info": {
            "read_cost": "2.03",
            "eval_cost": "0.60",
            "prefix_cost": "2.63",
            "data_read_per_join": "312"
          },
          "used_columns": [
            "feature_id",
            "purpose",
            "group_id"
          ]
        }
      },
      {
        "table": {
          "table_name": "g",
          "access_type": "ALL",
          "possible_keys": [
            "PRIMARY"
          ],
          "rows_examined_per_scan": 2,
          "rows_produced_per_join": 3,
          "filtered": "50.00",
          "using_join_buffer": "Block Nested Loop",
          "cost_info": {
            "read_cost": "2.02",
            "eval_cost": "0.60",
            "prefix_cost": "5.84",
            "data_read_per_join": "1K"
          },
          "used_columns": [
            "id",
            "code"
          ],
          "attached_condition": "(`atulecarter_march_setup`.`g`.`id` = `atulecarter_march_setup`.`f`.`group_id`)"
        }
      },
      {
        "table": {
          "table_name": "p",
          "access_type": "ALL",
          "possible_keys": [
            "PRIMARY",
            "idx_group_id"
          ],
          "rows_examined_per_scan": 9,
          "rows_produced_per_join": 13,
          "filtered": "49.38",
          "using_join_buffer": "Block Nested Loop",
          "cost_info": {
            "read_cost": "2.23",
            "eval_cost": "2.67",
            "prefix_cost": "12.88",
            "data_read_per_join": "213"
          },
          "used_columns": [
            "product_id",
            "parent_product_id",
            "group_id"
          ],
          "attached_condition": "((`atulecarter_march_setup`.`p`.`group_id` = `atulecarter_march_setup`.`f`.`group_id`) and (`atulecarter_march_setup`.`p`.`product_id` in (150,148,149,5,372,23,350,8)))"
        }
      }
    ]
  }
}