SELECT 
  category_id, 
  parent_id 
FROM 
  categories 
WHERE 
  parent_id IN(
    23245, 23251, 23244, 23243, 21737, 17295, 
    9662, 16788, 14608, 10407, 1329, 1123, 
    20529, 11840, 1326, 687, 20534, 1327, 
    18962, 20536, 509, 14866, 19037, 20533, 
    7460, 9505, 20532, 508, 20537, 7848, 
    3206, 507, 3212, 16952, 3216, 20535, 
    1072, 1330, 3352, 20530, 1334, 3210, 
    1332, 3215, 1333, 3208, 9500, 2410, 
    8997, 9604, 410, 511, 510, 16473, 16819, 
    8497, 1328, 16953, 3397, 9605, 513, 
    1301, 540, 23227
  )

Query time 0.00101

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "21.88"
    },
    "table": {
      "table_name": "categories",
      "access_type": "range",
      "possible_keys": [
        "parent"
      ],
      "key": "parent",
      "used_key_parts": [
        "parent_id"
      ],
      "key_length": "3",
      "rows_examined_per_scan": 106,
      "rows_produced_per_join": 106,
      "filtered": "100.00",
      "using_index": true,
      "cost_info": {
        "read_cost": "11.28",
        "eval_cost": "10.60",
        "prefix_cost": "21.88",
        "data_read_per_join": "277K"
      },
      "used_columns": [
        "category_id",
        "parent_id"
      ],
      "attached_condition": "(`goimagine`.`categories`.`parent_id` in (23245,23251,23244,23243,21737,17295,9662,16788,14608,10407,1329,1123,20529,11840,1326,687,20534,1327,18962,20536,509,14866,19037,20533,7460,9505,20532,508,20537,7848,3206,507,3212,16952,3216,20535,1072,1330,3352,20530,1334,3210,1332,3215,1333,3208,9500,2410,8997,9604,410,511,510,16473,16819,8497,1328,16953,3397,9605,513,1301,540,23227))"
    }
  }
}