SELECT 
  product_id, 
  group_id 
FROM 
  cscart_product_variation_group_products 
WHERE 
  group_id IN (
    255, 256, 254, 206, 184, 187, 189, 188, 
    183, 198, 35, 186, 185, 205, 180, 208, 
    224, 207, 218, 176, 181, 175, 212, 223, 
    174, 177, 217, 170, 211, 173, 216, 219, 
    148, 182, 215, 213, 179, 225, 227, 168, 
    171, 226, 172, 209, 222, 178, 197
  )

Query time 0.00055

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "36.51"
    },
    "table": {
      "table_name": "cscart_product_variation_group_products",
      "access_type": "range",
      "possible_keys": [
        "idx_group_id"
      ],
      "key": "idx_group_id",
      "used_key_parts": [
        "group_id"
      ],
      "key_length": "3",
      "rows_examined_per_scan": 55,
      "rows_produced_per_join": 55,
      "filtered": "100.00",
      "index_condition": "(`test_uchur_k`.`cscart_product_variation_group_products`.`group_id` in (255,256,254,206,184,187,189,188,183,198,35,186,185,205,180,208,224,207,218,176,181,175,212,223,174,177,217,170,211,173,216,219,148,182,215,213,179,225,227,168,171,226,172,209,222,178,197))",
      "cost_info": {
        "read_cost": "31.01",
        "eval_cost": "5.50",
        "prefix_cost": "36.51",
        "data_read_per_join": "880"
      },
      "used_columns": [
        "product_id",
        "group_id"
      ]
    }
  }
}

Result

product_id group_id
82 35
10 148
9 168
142 170
59 171
60 172
62 173
141 174
27 175
22 176
23 177
14 178
13 179
17 180
18 181
16 182
56 183
126 184
51295 185
117 185
116 186
115 187
81 188
11 189
63 197
51326 198
135 198
106 205
105 206
58 207
57 208
113 209
51344 211
120 211
51345 212
119 212
51346 213
118 213
114 215
108 216
4 217
5 218
107 219
6 222
51348 223
121 223
51349 224
122 224
61 225
51350 226
123 226
15 227
51496 254
51497 255
51498 256