SELECT 
  pfv.feature_id, 
  pfv.product_id, 
  pfv.variant_id, 
  gp.group_id 
FROM 
  cscart_product_features_values AS pfv 
  INNER JOIN cscart_product_variation_group_products AS gp ON pfv.product_id = gp.product_id 
  INNER JOIN cscart_product_variation_group_features AS gpf ON gpf.group_id = gp.group_id 
  AND gpf.feature_id = pfv.feature_id 
WHERE 
  pfv.lang_code = 'ru' 
  AND gp.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, 
    177, 174, 217, 170, 211, 173, 216, 219
  )

Query time 0.00101

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "51.71"
    },
    "nested_loop": [
      {
        "table": {
          "table_name": "gp",
          "access_type": "range",
          "possible_keys": [
            "PRIMARY",
            "idx_group_id"
          ],
          "key": "idx_group_id",
          "used_key_parts": [
            "group_id"
          ],
          "key_length": "3",
          "rows_examined_per_scan": 38,
          "rows_produced_per_join": 38,
          "filtered": "100.00",
          "index_condition": "(`test_uchur_k`.`gp`.`group_id` in (255,256,254,206,184,187,189,188,183,198,35,186,185,205,180,208,224,207,218,176,181,175,212,223,177,174,217,170,211,173,216,219))",
          "cost_info": {
            "read_cost": "21.31",
            "eval_cost": "3.80",
            "prefix_cost": "25.11",
            "data_read_per_join": "608"
          },
          "used_columns": [
            "product_id",
            "group_id"
          ]
        }
      },
      {
        "table": {
          "table_name": "gpf",
          "access_type": "ref",
          "possible_keys": [
            "PRIMARY",
            "idx_group_id"
          ],
          "key": "idx_group_id",
          "used_key_parts": [
            "group_id"
          ],
          "key_length": "3",
          "ref": [
            "test_uchur_k.gp.group_id"
          ],
          "rows_examined_per_scan": 1,
          "rows_produced_per_join": 38,
          "filtered": "100.00",
          "cost_info": {
            "read_cost": "9.50",
            "eval_cost": "3.80",
            "prefix_cost": "38.41",
            "data_read_per_join": "3K"
          },
          "used_columns": [
            "feature_id",
            "group_id"
          ]
        }
      },
      {
        "table": {
          "table_name": "pfv",
          "access_type": "ref",
          "possible_keys": [
            "PRIMARY",
            "fl",
            "lang_code",
            "product_id",
            "fpl",
            "idx_product_feature_variant_id"
          ],
          "key": "fpl",
          "used_key_parts": [
            "feature_id",
            "product_id",
            "lang_code"
          ],
          "key_length": "12",
          "ref": [
            "test_uchur_k.gpf.feature_id",
            "test_uchur_k.gp.product_id",
            "const"
          ],
          "rows_examined_per_scan": 1,
          "rows_produced_per_join": 38,
          "filtered": "100.00",
          "cost_info": {
            "read_cost": "9.50",
            "eval_cost": "3.80",
            "prefix_cost": "51.71",
            "data_read_per_join": "29K"
          },
          "used_columns": [
            "feature_id",
            "product_id",
            "variant_id",
            "lang_code"
          ]
        }
      }
    ]
  }
}

Result

feature_id product_id variant_id group_id
3 82 6 35
193 142 1373 170
193 62 1373 173
193 141 1373 174
193 27 1373 175
193 22 1373 176
193 23 1373 177
193 17 1373 180
193 18 1373 181
193 56 1373 183
193 126 1373 184
193 51295 1376 185
193 117 1375 185
193 116 1375 186
193 115 1375 187
193 81 1373 188
193 11 1373 189
193 51326 1379 198
193 135 1380 198
193 106 1373 205
193 105 1373 206
193 58 1373 207
193 57 1373 208
193 51344 1386 211
193 120 1385 211
193 51345 1386 212
193 119 1385 212
193 108 1373 216
193 4 1373 217
193 5 1373 218
193 107 1373 219
193 51348 1386 223
193 121 1385 223
193 51349 1386 224
193 122 1385 224
193 51496 1373 254
193 51497 1373 255
193 51498 1373 256