SELECT 
  pfv.variant_id, 
  pfv.position, 
  pfvd.variant 
FROM 
  cscart_product_feature_variants AS pfv 
  INNER JOIN cscart_product_feature_variant_descriptions AS pfvd ON pfv.variant_id = pfvd.variant_id 
  AND pfvd.lang_code = 'vi' 
WHERE 
  pfv.variant_id IN (
    73924, 73923, 79318, 79319, 86299, 86298, 
    86297, 86300, 87462, 87461, 86301, 
    87464, 87463, 86303, 86302, 87452, 
    87451, 87456, 87455, 87458, 87457, 
    87460, 87459
  )

Query time 0.00267

JSON explain

{
  "query_block": {
    "select_id": 1,
    "nested_loop": [
      {
        "table": {
          "table_name": "pfv",
          "access_type": "range",
          "possible_keys": ["PRIMARY"],
          "key": "PRIMARY",
          "key_length": "3",
          "used_key_parts": ["variant_id"],
          "rows": 23,
          "filtered": 100,
          "index_condition": "pfv.variant_id in (73924,73923,79318,79319,86299,86298,86297,86300,87462,87461,86301,87464,87463,86303,86302,87452,87451,87456,87455,87458,87457,87460,87459)"
        }
      },
      {
        "table": {
          "table_name": "pfvd",
          "access_type": "eq_ref",
          "possible_keys": ["PRIMARY"],
          "key": "PRIMARY",
          "key_length": "9",
          "used_key_parts": ["variant_id", "lang_code"],
          "ref": ["dev_db.pfv.variant_id", "const"],
          "rows": 1,
          "filtered": 100,
          "index_condition": "pfvd.lang_code = 'vi'"
        }
      }
    ]
  }
}