SELECT 
  category_id, 
  parent_id 
FROM 
  categories 
WHERE 
  parent_id IN(
    6724, 6718, 6713, 6691, 6685, 24, 6655, 
    6668, 6692, 6683, 92, 93, 62, 6656, 6669, 
    6661, 6684, 6725, 6679, 25, 6719, 6726, 
    6657, 6670, 6680, 26, 6662, 6663, 6671, 
    6658, 6681, 27, 6672, 9936, 6659, 28, 
    6686, 6673, 6720, 6674, 94, 6723, 96, 
    97, 98, 2185
  )

Query time 0.00090

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "18.27"
    },
    "table": {
      "table_name": "categories",
      "access_type": "range",
      "possible_keys": [
        "parent"
      ],
      "key": "parent",
      "used_key_parts": [
        "parent_id"
      ],
      "key_length": "3",
      "rows_examined_per_scan": 88,
      "rows_produced_per_join": 88,
      "filtered": "100.00",
      "using_index": true,
      "cost_info": {
        "read_cost": "9.47",
        "eval_cost": "8.80",
        "prefix_cost": "18.27",
        "data_read_per_join": "230K"
      },
      "used_columns": [
        "category_id",
        "parent_id"
      ],
      "attached_condition": "(`goimagine`.`categories`.`parent_id` in (6724,6718,6713,6691,6685,24,6655,6668,6692,6683,92,93,62,6656,6669,6661,6684,6725,6679,25,6719,6726,6657,6670,6680,26,6662,6663,6671,6658,6681,27,6672,9936,6659,28,6686,6673,6720,6674,94,6723,96,97,98,2185))"
    }
  }
}