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 (
    71341, 71340, 71339, 71338, 71337, 71336, 
    71335, 71334, 71333, 71332, 71331, 
    71342, 82141, 82144, 82145, 82146, 
    82147, 82148, 82149, 82150, 82143, 
    82142, 82153, 82152, 82151, 82207, 
    82217, 82218, 82219, 82220, 82221, 
    82222, 82223, 82224, 82225, 82208, 
    82209, 82210, 82211, 82212, 82213, 
    82214, 82215, 82216, 86810, 86800, 
    86801, 86802, 86803, 86804, 86805, 
    86806, 86807
  )

Query time 0.00591

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": 53,
          "filtered": 100,
          "index_condition": "pfv.variant_id in (71341,71340,71339,71338,71337,71336,71335,71334,71333,71332,71331,71342,82141,82144,82145,82146,82147,82148,82149,82150,82143,82142,82153,82152,82151,82207,82217,82218,82219,82220,82221,82222,82223,82224,82225,82208,82209,82210,82211,82212,82213,82214,82215,82216,86810,86800,86801,86802,86803,86804,86805,86806,86807)"
        }
      },
      {
        "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'"
        }
      }
    ]
  }
}