SELECT 
  a.*, 
  b.option_name, 
  b.internal_option_name, 
  b.option_text, 
  b.description, 
  b.inner_hint, 
  b.incorrect_message, 
  b.comment 
FROM 
  cscart_product_options as a 
  LEFT JOIN cscart_product_options_descriptions as b ON a.option_id = b.option_id 
  AND b.lang_code = 'ja' 
WHERE 
  a.product_id IN (7, 6, 5, 4, 3, 2, 1) 
  AND a.status = 'A' 
ORDER BY 
  a.position

Query time 0.00050

JSON explain

{
  "query_block": {
    "select_id": 1,
    "ordering_operation": {
      "using_filesort": true,
      "nested_loop": [
        {
          "table": {
            "table_name": "a",
            "access_type": "ALL",
            "possible_keys": [
              "c_status"
            ],
            "rows": 4,
            "filtered": 100,
            "attached_condition": "((`_testcscart`.`a`.`product_id` in (7,6,5,4,3,2,1)) and (`_testcscart`.`a`.`status` = 'A'))"
          }
        },
        {
          "table": {
            "table_name": "b",
            "access_type": "eq_ref",
            "possible_keys": [
              "PRIMARY"
            ],
            "key": "PRIMARY",
            "used_key_parts": [
              "option_id",
              "lang_code"
            ],
            "key_length": "9",
            "ref": [
              "_testcscart.a.option_id",
              "const"
            ],
            "rows": 1,
            "filtered": 100,
            "attached_condition": "<if>(is_not_null_compl(b), (`_testcscart`.`b`.`lang_code` = 'ja'), true)"
          }
        }
      ]
    }
  }
}