SELECT 
  category_id, 
  parent_id 
FROM 
  categories 
WHERE 
  parent_id IN(
    512, 411, 414, 426, 1549, 412, 3225, 418, 
    423, 413, 424, 425, 417, 421, 415, 419, 
    422, 2221, 416
  )

Query time 0.00061

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "4.48"
    },
    "table": {
      "table_name": "categories",
      "access_type": "range",
      "possible_keys": [
        "parent"
      ],
      "key": "parent",
      "used_key_parts": [
        "parent_id"
      ],
      "key_length": "3",
      "rows_examined_per_scan": 19,
      "rows_produced_per_join": 19,
      "filtered": "100.00",
      "using_index": true,
      "cost_info": {
        "read_cost": "2.58",
        "eval_cost": "1.90",
        "prefix_cost": "4.48",
        "data_read_per_join": "49K"
      },
      "used_columns": [
        "category_id",
        "parent_id"
      ],
      "attached_condition": "(`goimagine`.`categories`.`parent_id` in (512,411,414,426,1549,412,3225,418,423,413,424,425,417,421,415,419,422,2221,416))"
    }
  }
}