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 (
    12888, 12889, 15862, 15864, 12737, 12892, 
    14830, 15624, 12881, 15865, 16663, 
    14827, 16312, 14634, 15854, 15644, 
    14838, 15857, 16310, 16315, 16457, 
    14516, 16945, 12887, 15852, 12882, 
    15626
  )

Query time 0.00492

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": 114,
          "filtered": 100,
          "index_condition": "gp.group_id in (12888,12889,15862,15864,12737,12892,14830,15624,12881,15865,16663,14827,16312,14634,15854,15644,14838,15857,16310,16315,16457,14516,16945,12887,15852,12882,15626)"
        }
      },
      {
        "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
        }
      }
    ]
  }
}