SELECT 
  category_id, 
  parent_id 
FROM 
  cscart_categories 
WHERE 
  parent_id IN(
    34536, 30714, 5087, 5081, 2535, 5167, 
    5098, 5076, 5097, 5100, 7160, 28376, 
    7109, 28375, 7222, 5774, 5773, 6942, 
    11917, 7158, 7159, 5467, 3005, 28964, 
    7161
  )

Query time 0.00036

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "5.64"
    },
    "table": {
      "table_name": "cscart_categories",
      "access_type": "range",
      "possible_keys": [
        "parent"
      ],
      "key": "parent",
      "used_key_parts": [
        "parent_id"
      ],
      "key_length": "3",
      "rows_examined_per_scan": 25,
      "rows_produced_per_join": 25,
      "filtered": "100.00",
      "using_index": true,
      "cost_info": {
        "read_cost": "3.15",
        "eval_cost": "2.50",
        "prefix_cost": "5.65",
        "data_read_per_join": "64K"
      },
      "used_columns": [
        "category_id",
        "parent_id"
      ],
      "attached_condition": "(`maniamall_cscart`.`cscart_categories`.`parent_id` in (34536,30714,5087,5081,2535,5167,5098,5076,5097,5100,7160,28376,7109,28375,7222,5774,5773,6942,11917,7158,7159,5467,3005,28964,7161))"
    }
  }
}

Result