SELECT 
  category_id, 
  parent_id 
FROM 
  cscart_categories 
WHERE 
  parent_id IN(
    235, 167, 168, 198, 176, 178, 190, 255, 
    182, 175, 197, 236, 185, 169, 191, 193, 
    199, 240, 179, 186, 174, 234, 194, 200, 
    180, 238, 202, 187, 181, 195, 177, 237, 
    196, 188, 254, 189, 165, 170, 171, 172, 
    201, 263
  )

Query time 0.00034

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "20.08"
    },
    "table": {
      "table_name": "cscart_categories",
      "access_type": "ALL",
      "possible_keys": [
        "parent"
      ],
      "rows_examined_per_scan": 83,
      "rows_produced_per_join": 67,
      "filtered": "81.93",
      "cost_info": {
        "read_cost": "6.48",
        "eval_cost": "13.60",
        "prefix_cost": "20.08",
        "data_read_per_join": "176K"
      },
      "used_columns": [
        "category_id",
        "parent_id"
      ],
      "attached_condition": "(`atulecarter_atul_demo5`.`cscart_categories`.`parent_id` in (235,167,168,198,176,178,190,255,182,175,197,236,185,169,191,193,199,240,179,186,174,234,194,200,180,238,202,187,181,195,177,237,196,188,254,189,165,170,171,172,201,263))"
    }
  }
}