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 (
    80725, 80726, 80727, 80728, 80729, 80730, 
    80731, 80732, 80733, 80734, 80735, 
    80736, 80737, 80743, 80744, 80745, 
    80746, 86895, 86896, 86897, 80747, 
    80748, 80749, 80750, 80751, 80752, 
    80753, 80754, 80755, 80756, 80765, 
    80757, 80758, 80759, 80760, 80761, 
    80762, 80763, 80764
  )

Query time 0.00989

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": 39,
          "filtered": 100,
          "index_condition": "pfv.variant_id in (80725,80726,80727,80728,80729,80730,80731,80732,80733,80734,80735,80736,80737,80743,80744,80745,80746,86895,86896,86897,80747,80748,80749,80750,80751,80752,80753,80754,80755,80756,80765,80757,80758,80759,80760,80761,80762,80763,80764)"
        }
      },
      {
        "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'"
        }
      }
    ]
  }
}