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 (
    68796, 68795, 71575, 71573, 71574, 74588, 
    74590, 74591, 74593, 74594, 74596, 
    76637, 76635, 76636, 80580, 80581, 
    80582, 80583, 80584, 80585, 80586, 
    81495, 81496, 83821, 83822, 83823, 
    83824, 83825
  )

Query time 0.00515

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": 28,
          "filtered": 100,
          "index_condition": "pfv.variant_id in (68796,68795,71575,71573,71574,74588,74590,74591,74593,74594,74596,76637,76635,76636,80580,80581,80582,80583,80584,80585,80586,81495,81496,83821,83822,83823,83824,83825)"
        }
      },
      {
        "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'"
        }
      }
    ]
  }
}