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 (
    75773, 75771, 87264, 75772, 75795, 75791, 
    75792, 75793, 75794, 80929, 81898, 
    81905, 81906, 81907, 81908, 81909, 
    81899, 81900, 81901, 81902, 81903, 
    81904, 82708, 82709, 82710, 82711, 
    82712, 82713, 87232, 87233, 87263
  )

Query time 0.00347

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": 31,
          "filtered": 100,
          "index_condition": "pfv.variant_id in (75773,75771,87264,75772,75795,75791,75792,75793,75794,80929,81898,81905,81906,81907,81908,81909,81899,81900,81901,81902,81903,81904,82708,82709,82710,82711,82712,82713,87232,87233,87263)"
        }
      },
      {
        "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'"
        }
      }
    ]
  }
}