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 = 'en' 
  AND gp.group_id IN (
    345, 418, 252, 681, 155, 466, 666, 353, 
    381, 212, 266, 664, 383, 648, 432, 373, 
    382, 673, 689
  )

Query time 0.00209

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "53.21"
    },
    "nested_loop": [
      {
        "table": {
          "table_name": "gpf",
          "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": 19,
          "rows_produced_per_join": 19,
          "filtered": "100.00",
          "index_condition": "(`softwarepirmam_hewadelivard_cscart_4`.`gpf`.`group_id` in (345,418,252,681,155,466,666,353,381,212,266,664,383,648,432,373,382,673,689))",
          "cost_info": {
            "read_cost": "11.41",
            "eval_cost": "1.90",
            "prefix_cost": "13.31",
            "data_read_per_join": "1K"
          },
          "used_columns": [
            "feature_id",
            "group_id"
          ]
        }
      },
      {
        "table": {
          "table_name": "gp",
          "access_type": "ref",
          "possible_keys": [
            "PRIMARY",
            "idx_group_id"
          ],
          "key": "idx_group_id",
          "used_key_parts": [
            "group_id"
          ],
          "key_length": "3",
          "ref": [
            "softwarepirmam_hewadelivard_cscart_4.gpf.group_id"
          ],
          "rows_examined_per_scan": 3,
          "rows_produced_per_join": 57,
          "filtered": "100.00",
          "cost_info": {
            "read_cost": "14.25",
            "eval_cost": "5.70",
            "prefix_cost": "33.26",
            "data_read_per_join": "912"
          },
          "used_columns": [
            "product_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": [
            "softwarepirmam_hewadelivard_cscart_4.gpf.feature_id",
            "softwarepirmam_hewadelivard_cscart_4.gp.product_id",
            "const"
          ],
          "rows_examined_per_scan": 1,
          "rows_produced_per_join": 57,
          "filtered": "100.00",
          "cost_info": {
            "read_cost": "14.25",
            "eval_cost": "5.70",
            "prefix_cost": "53.21",
            "data_read_per_join": "44K"
          },
          "used_columns": [
            "feature_id",
            "product_id",
            "variant_id",
            "lang_code"
          ]
        }
      }
    ]
  }
}

Result

feature_id product_id variant_id group_id
656 2227 1600 155
656 2226 2315 155
656 2522 1560 212
656 2655 1559 252
656 2719 1600 266
656 2728 2993 266
656 3112 1560 345
656 3113 1559 345
656 3042 1560 353
656 3153 1559 353
656 3290 1560 373
656 3289 1559 373
656 3377 1559 381
656 3378 1560 381
656 3382 1560 382
656 3383 1559 382
656 3385 1560 383
656 3386 1559 383
656 3664 1560 418
656 3665 1559 418
656 3832 1560 432
656 3831 1559 432
656 4110 1560 466
656 4111 1913 466
656 3811 1558 466
656 5948 1560 648
656 6128 6250 648
656 6127 2077 648
656 6126 1599 648
656 6129 6252 648
656 6130 6253 648
656 6131 6257 648
656 6132 6258 648
656 6133 6360 648
656 6134 7010 648
656 6135 1610 648
656 6041 1598 664
656 6042 1556 664
656 6043 1560 664
656 6044 1596 664
656 6045 6252 664
656 6046 6258 664
656 6047 7534 664
656 6054 1598 666
656 6055 1556 666
656 6056 1560 666
656 6057 1596 666
656 6058 6252 666
656 6059 6258 666
656 5956 1560 673
656 6087 1600 673
656 6088 6284 673
656 6089 6285 673
656 6090 6290 673
656 6091 6360 673
656 6092 6995 673
656 6093 7064 673
656 5683 1560 681
656 6152 1600 681
656 6153 1913 681
656 6154 5517 681
656 6155 1753 681
656 6196 1596 689
656 6195 1560 689
656 6194 1556 689
656 6197 2077 689
656 6198 6250 689
656 6199 6252 689
656 6200 6253 689
656 6201 6255 689
656 6202 6256 689