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 (
    74435, 74436, 74438, 84080, 84081, 84082, 
    84083, 84084, 84085, 85130, 85129, 
    85128, 85127, 85266, 85267, 85539, 
    85538, 85540, 85541, 85960, 85961, 
    85962, 85963, 85964, 85965, 85966, 
    85967, 86054, 86055, 86053, 86057, 
    86056, 86900, 86901, 86902
  )

Query time 0.00282

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 (74435,74436,74438,84080,84081,84082,84083,84084,84085,85130,85129,85128,85127,85266,85267,85539,85538,85540,85541,85960,85961,85962,85963,85964,85965,85966,85967,86054,86055,86053,86057,86056,86900,86901,86902)"
        }
      },
      {
        "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'"
        }
      }
    ]
  }
}