SELECT 
  category_id, 
  parent_id 
FROM 
  cscart_categories 
WHERE 
  parent_id IN(
    9531, 
    9536, 
    3609, 
    3549, 
    3795, 
    8449, 
    3552, 
    3629, 
    3829, 
    8452, 
    3656, 
    8465, 
    3632, 
    3569, 
    3880, 
    3572, 
    3641, 
    3910, 
    8466, 
    8467, 
    3599, 
    3647, 
    3931, 
    3638, 
    3652, 
    3951, 
    9014, 
    6316, 
    3655, 
    3663, 
    3671, 
    3675, 
    3680, 
    3682, 
    3620, 
    3670, 
    3681, 
    3701, 
    3721, 
    3748, 
    3776, 
    3688, 
    3987, 
    4137, 
    3689, 
    4295, 
    3692, 
    5062, 
    3695, 
    5357, 
    3698, 
    5513, 
    3703, 
    3707, 
    5566, 
    5613, 
    3711, 
    5680, 
    3719, 
    5754, 
    3725, 
    5966, 
    3730, 
    6065, 
    3734, 
    6248, 
    3744, 
    6475, 
    3755, 
    6547, 
    3763, 
    6643, 
    3769, 
    7160, 
    3782, 
    7228, 
    3791, 
    7296, 
    3799, 
    7465, 
    3802, 
    6630, 
    7671, 
    6482, 
    3809, 
    7722, 
    3814, 
    7780, 
    3818, 
    8220, 
    3822, 
    8301, 
    3826, 
    8347, 
    3834, 
    3838, 
    8367, 
    3844, 
    3849, 
    4290, 
    3856, 
    8396, 
    3865, 
    4403, 
    8416, 
    8420, 
    3882, 
    4666, 
    3889, 
    5018, 
    5115, 
    3894, 
    5254, 
    3906, 
    5329, 
    3909, 
    5410, 
    3916, 
    5471, 
    3921, 
    5580, 
    3926, 
    5658, 
    3929, 
    5886, 
    3941, 
    6069, 
    6370, 
    6573, 
    6856, 
    6881, 
    7235, 
    7397, 
    7631, 
    7654, 
    9011, 
    9013
  )

Query time 0.00134

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "104.40"
    },
    "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": 258,
      "rows_produced_per_join": 258,
      "filtered": "100.00",
      "using_index": true,
      "cost_info": {
        "read_cost": "52.80",
        "eval_cost": "51.60",
        "prefix_cost": "104.40",
        "data_read_per_join": "1M"
      },
      "used_columns": [
        "category_id",
        "parent_id"
      ],
      "attached_condition": "(`webmarco`.`cscart_categories`.`parent_id` in (9531,9536,3609,3549,3795,8449,3552,3629,3829,8452,3656,8465,3632,3569,3880,3572,3641,3910,8466,8467,3599,3647,3931,3638,3652,3951,9014,6316,3655,3663,3671,3675,3680,3682,3620,3670,3681,3701,3721,3748,3776,3688,3987,4137,3689,4295,3692,5062,3695,5357,3698,5513,3703,3707,5566,5613,3711,5680,3719,5754,3725,5966,3730,6065,3734,6248,3744,6475,3755,6547,3763,6643,3769,7160,3782,7228,3791,7296,3799,7465,3802,6630,7671,6482,3809,7722,3814,7780,3818,8220,3822,8301,3826,8347,3834,3838,8367,3844,3849,4290,3856,8396,3865,4403,8416,8420,3882,4666,3889,5018,5115,3894,5254,3906,5329,3909,5410,3916,5471,3921,5580,3926,5658,3929,5886,3941,6069,6370,6573,6856,6881,7235,7397,7631,7654,9011,9013))"
    }
  }
}

Result

category_id parent_id
3632 3549
3641 3549
3647 3549
3652 3549
3655 3549
3663 3549
3671 3549
3675 3549
3680 3549
3682 3549
3688 3549
3689 3549
3692 3549
3695 3549
3698 3549
3703 3549
3707 3549
3711 3549
3719 3549
3725 3549
3730 3549
3734 3549
3744 3549
3755 3549
3763 3549
3769 3549
3782 3549
3791 3549
3799 3549
3802 3549
3809 3549
3814 3549
3818 3549
3822 3549
3826 3549
3834 3549
3838 3549
3844 3549
3849 3549
4290 3549
4403 3549
4666 3549
5018 3549
5115 3549
5254 3549
5329 3549
5410 3549
5471 3549
5580 3549
5658 3549
5886 3549
6069 3549
6370 3549
6573 3549
6881 3549
7235 3549
7397 3549
7654 3549
3609 3638
3620 3638
3629 3638
3656 3638
3670 3638
3681 3638
3701 3638
3721 3638
3748 3638
3776 3638
4137 3638
4295 3638
5062 3638
5357 3638
5513 3638
5566 3638
5613 3638
5680 3638
5754 3638
5966 3638
6065 3638
6248 3638
6475 3638
6547 3638
6643 3638
6856 3638
7160 3638
7228 3638
7296 3638
7465 3638
7631 3638
7671 3638
7722 3638
7780 3638
8220 3638
8301 3638
8347 3638
8367 3638
8396 3638
8416 3638
8420 3638
9011 3638
9013 3638
3856 3671
3865 3671
3882 3671
3889 3671
3894 3671
3906 3671
3909 3671
3916 3671
3921 3671
3926 3671
3929 3671
3941 3671
3795 3776
3829 3776
3880 3776
3910 3776
3931 3776
3951 3776
3987 3776
8449 8367
8452 8367
8465 8367
8466 8367
8467 8367
9014 8367