SELECT 
  category_id, 
  parent_id 
FROM 
  cscart_categories 
WHERE 
  parent_id IN(
    535, 522, 546, 539, 588, 534, 590, 547, 
    536, 540, 538, 541, 571, 591, 545, 537
  ) 
  AND category_id != 264

Query time 0.00058

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "13.46"
    },
    "table": {
      "table_name": "cscart_categories",
      "access_type": "range",
      "possible_keys": [
        "PRIMARY",
        "parent",
        "p_category_id"
      ],
      "key": "parent",
      "used_key_parts": [
        "parent_id"
      ],
      "key_length": "3",
      "rows_examined_per_scan": 21,
      "rows_produced_per_join": 21,
      "filtered": "100.00",
      "index_condition": "(`softwarepirmam_hewadelivard_cscart_4`.`cscart_categories`.`parent_id` in (535,522,546,539,588,534,590,547,536,540,538,541,571,591,545,537))",
      "cost_info": {
        "read_cost": "11.36",
        "eval_cost": "2.10",
        "prefix_cost": "13.46",
        "data_read_per_join": "65K"
      },
      "used_columns": [
        "category_id",
        "parent_id"
      ],
      "attached_condition": "(`softwarepirmam_hewadelivard_cscart_4`.`cscart_categories`.`category_id` <> 264)"
    }
  }
}