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 = 'vi' 
  AND gp.group_id IN (
    17246, 13678, 12971, 13155, 16321, 13255, 
    13152, 13683, 17017, 16101, 15072, 
    15879, 16065, 13676, 13666, 13765, 
    13443, 13679
  )

Query time 0.01859

JSON explain

{
  "query_block": {
    "select_id": 1,
    "nested_loop": [
      {
        "table": {
          "table_name": "gp",
          "access_type": "range",
          "possible_keys": ["PRIMARY", "idx_group_id"],
          "key": "idx_group_id",
          "key_length": "3",
          "used_key_parts": ["group_id"],
          "rows": 86,
          "filtered": 100,
          "index_condition": "gp.group_id in (17246,13678,12971,13155,16321,13255,13152,13683,17017,16101,15072,15879,16065,13676,13666,13765,13443,13679)"
        }
      },
      {
        "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": ["dev_db.gp.group_id"],
          "rows": 1,
          "filtered": 100
        }
      },
      {
        "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": ["dev_db.gp.product_id", "dev_db.gpf.feature_id", "const"],
          "rows": 1,
          "filtered": 100,
          "attached_condition": "pfv.lang_code = 'vi'",
          "using_index": true
        }
      }
    ]
  }
}