SELECT 
  category_id, 
  parent_id 
FROM 
  cscart_categories 
WHERE 
  parent_id IN(
    356, 10667, 1584, 344, 394, 2404, 443, 
    1936, 1907, 990, 930, 1498, 341, 327, 
    715, 2171, 2178, 2373, 2433, 2465, 2577, 
    2591, 2611, 2615, 9692, 9830, 9840, 
    9844, 9926, 9936, 10631, 10632, 10633
  )

Query time 0.00119

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "69.53"
    },
    "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": 171,
      "rows_produced_per_join": 171,
      "filtered": "100.00",
      "using_index": true,
      "cost_info": {
        "read_cost": "35.33",
        "eval_cost": "34.20",
        "prefix_cost": "69.53",
        "data_read_per_join": "1013K"
      },
      "used_columns": [
        "category_id",
        "parent_id"
      ],
      "attached_condition": "(`webmarco`.`cscart_categories`.`parent_id` in (356,10667,1584,344,394,2404,443,1936,1907,990,930,1498,341,327,715,2171,2178,2373,2433,2465,2577,2591,2611,2615,9692,9830,9840,9844,9926,9936,10631,10632,10633))"
    }
  }
}

Result

category_id parent_id
328 327
1018 327
1438 327
1695 327
2528 327
2566 327
2567 327
2597 327
342 341
343 341
397 341
345 344
346 344
348 344
349 344
352 344
2595 344
9264 344
393 356
396 356
929 356
1506 356
1714 356
1715 356
1914 356
2397 356
2468 356
2529 356
2552 356
9290 356
395 394
398 394
399 394
1861 394
2389 394
2554 394
9294 394
9623 394
9921 394
9922 394
9923 394
9924 394
9940 394
9941 394
9942 394
9943 394
267 443
444 443
445 443
446 443
447 443
1409 443
1410 443
1505 443
1509 443
1510 443
1518 443
1690 443
2454 443
2610 443
2634 443
9842 443
9843 443
10425 443
10426 443
716 715
1315 715
932 930
935 930
945 930
8944 930
9961 930
991 990
992 990
994 990
2265 990
1479 1498
1499 1498
1500 1498
2386 1498
2469 1498
2553 1498
1303 1584
1309 1584
2473 1584
2596 1584
2613 1584
9958 1584
1908 1907
1909 1907
1910 1907
1911 1907
1912 1907
1913 1907
2180 1907
9849 1907
9864 1907
1937 1936
1938 1936
1939 1936
2579 1936
2580 1936
2583 1936
2584 1936
2585 1936
2586 1936
2601 1936
9929 1936
2172 2171
2173 2171
2179 2178
2370 2178
2371 2178
2372 2178
2559 2178
9748 2178
9749 2178
9750 2178
2374 2373
2388 2373
2405 2404
2539 2404
2540 2404
2176 2433
2434 2433
2478 2433
2549 2433
2466 2465
2467 2465
2578 2577
2604 2577
2623 2577
9867 2577
9920 2577
10247 2577
10248 2577
2592 2591
2593 2591
2594 2591
1306 2611
2612 2611
2616 2615
2617 2615
9693 9692
9694 9692
9841 9840
9845 9844
9846 9844
9847 9844
9848 9844
9855 9844
9856 9844
9857 9844
9858 9844
9859 9844
9860 9844
9861 9844
9862 9844
9863 9844
9865 9844
9866 9844
9918 9844
9919 9844
9927 9926
9928 9926
10669 10667