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 (
    77662, 77658, 77659, 77660, 77661, 78622, 
    78621, 80747, 80748, 80749, 80750, 
    80751, 80752, 80753, 80754, 80755, 
    82376, 82378, 82379, 82380, 82377, 
    82394, 82395, 82396, 86319, 86318, 
    86317, 86316, 87006, 87007, 87008, 
    87009, 87010, 87298, 87300
  )

Query time 0.00227

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": 35,
          "filtered": 100,
          "index_condition": "pfv.variant_id in (77662,77658,77659,77660,77661,78622,78621,80747,80748,80749,80750,80751,80752,80753,80754,80755,82376,82378,82379,82380,82377,82394,82395,82396,86319,86318,86317,86316,87006,87007,87008,87009,87010,87298,87300)"
        }
      },
      {
        "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'"
        }
      }
    ]
  }
}