SELECT 
  category_id, 
  parent_id 
FROM 
  cscart_categories 
WHERE 
  parent_id IN(
    2934, 2935, 2936, 2937, 2686, 2687, 2938, 
    2939, 3155, 3157, 3158, 3156, 3190, 
    3154, 3654, 3653, 2456, 2457, 3553, 
    3544, 2458, 2459, 2460, 2461, 2462, 
    2463, 2362, 384, 2396, 3160, 3161, 3159, 
    3126, 3131, 3640, 3641, 3162, 2464, 
    2646, 2647, 2648, 2465, 310, 311, 312, 
    151, 2318, 152, 3, 5, 4, 108, 186, 187, 
    154, 153, 155, 156, 366, 2684, 2685, 
    2940, 2941, 2942, 2943, 2944, 2945, 
    2946, 2947, 2948, 3540, 3449, 3450, 
    3451, 3452, 3667, 3746, 3753, 3786, 
    3883, 3899, 3906
  )

Query time 0.00054

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "table_name": "cscart_categories",
      "access_type": "range",
      "possible_keys": ["parent"],
      "key": "parent",
      "key_length": "3",
      "used_key_parts": ["parent_id"],
      "rows": 82,
      "filtered": 100,
      "index_condition": "cscart_categories.parent_id in (2934,2935,2936,2937,2686,2687,2938,2939,3155,3157,3158,3156,3190,3154,3654,3653,2456,2457,3553,3544,2458,2459,2460,2461,2462,2463,2362,384,2396,3160,3161,3159,3126,3131,3640,3641,3162,2464,2646,2647,2648,2465,310,311,312,151,2318,152,3,5,4,108,186,187,154,153,155,156,366,2684,2685,2940,2941,2942,2943,2944,2945,2946,2947,2948,3540,3449,3450,3451,3452,3667,3746,3753,3786,3883,3899,3906)"
    }
  }
}