how to delete the latest some records in --safe-updates mode

e.g. I want to delete the latest three records in below table

root@localhost:[test]10:14:02>select * from delete_test order by create_time desc;
+----+------+---------------------+
| id | code | create_time         |
+----+------+---------------------+
|  9 | fff  | 2016-06-18 10:08:28 |
|  8 | eee  | 2016-06-18 10:08:21 |
|  7 | ddd  | 2016-06-18 10:08:15 |
|  3 | ccc  | 2016-06-17 22:18:48 |
|  2 | bbb  | 2016-06-17 22:18:42 |
|  1 | aaa  | 2016-06-17 22:18:37 |
+----+------+---------------------+

first I tried

root@localhost:[test]10:14:14>delete from delete_test where code in (select code from delete_test order by create_time desc limit 3);
ERROR 1235 (42000): This version of MySQL doesn't yet support 'LIMIT & IN/ALL/ANY/SOME subquery'

then I tried

root@localhost:[test]10:17:05>delete a from delete_test a, (select code from delete_test order by create_time desc limit 3) b where a.code = b.code;
ERROR 1175 (HY000): You are using safe update mode and you tried to update a table without a WHERE that uses a KEY column

but code filed is unique key.

then I tried

root@localhost:[test]10:18:49>delete a from delete_test a join (select code from delete_test order by create_time desc limit 3) b on a.code = b.code where a.id>0;
ERROR 1175 (HY000): You are using safe update mode and you tried to update a table without a WHERE that uses a KEY column

but I used primary key explicitly.

So I want to know how to delete the latest some records in --safe-updates mode?