The most recent rows in for each type/agent

I have a table (still on MySQL 5.7) with lots of data. This table is written by some scripts. It works like a "checkin", where each agent is checking in in some period of time. It looks like below. | id | agent | status | timestamp | |----|-------|--------|----------|-----------| | 1 | tom | ok | 2023-03-16 12:27:03 | | 2 | jeff | degraded | 2023-08-31 00:01:13 | 100 | tom | ok | 2023-10-03 12:00:00 | | 101 | jeff | ok | 2023-10-03 11:59:00 | I'd like to pick the most fresh line per each agent. So in above example I'd like to get row 100 and 101. I use following script, but it turns out only first two rows. I tried changing order by id or timestamp ASC/DESC. SELECT * FROM (SELECT * FROM db_table ORDER BY timestamp ASC) as agnt GROUP BY agent How to make it working?