SELECT 
  pfv.feature_id, 
  pfv.product_id, 
  pfv.variant_id, 
  gp.group_id 
FROM 
  vi_product_features_values AS pfv 
  INNER JOIN vi_product_variation_group_products AS gp ON pfv.product_id = gp.product_id 
  INNER JOIN vi_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 (10)

Query time 0.00018

JSON explain

{
  "query_block": {
    "select_id": 1,
    "nested_loop": [
      {
        "table": {
          "table_name": "gpf",
          "access_type": "ref",
          "possible_keys": ["PRIMARY", "idx_group_id"],
          "key": "idx_group_id",
          "key_length": "3",
          "used_key_parts": ["group_id"],
          "ref": ["const"],
          "rows": 2,
          "filtered": 100
        }
      },
      {
        "block-nl-join": {
          "table": {
            "table_name": "gp",
            "access_type": "index",
            "possible_keys": ["PRIMARY", "idx_group_id"],
            "key": "PRIMARY",
            "key_length": "6",
            "used_key_parts": ["product_id", "group_id"],
            "rows": 11,
            "filtered": 63.63636398,
            "attached_condition": "gp.group_id = 10",
            "using_index": true
          },
          "buffer_type": "flat",
          "buffer_size": "86",
          "join_type": "BNL"
        }
      },
      {
        "table": {
          "table_name": "pfv",
          "access_type": "ref",
          "possible_keys": [
            "PRIMARY",
            "fl",
            "lang_code",
            "product_id",
            "fpl",
            "idx_product_feature_variant_id"
          ],
          "key": "idx_product_feature_variant_id",
          "key_length": "12",
          "used_key_parts": ["product_id", "feature_id", "lang_code"],
          "ref": [
            "devvipiriscom.gp.product_id",
            "devvipiriscom.gpf.feature_id",
            "const"
          ],
          "rows": 1,
          "filtered": 100,
          "attached_condition": "pfv.lang_code = 'en'",
          "using_index": true
        }
      }
    ]
  }
}