Seems this doesn't fix the issue? Also it shouldn't really be a problem I think as when using the API concurrently we would see these issues as well maybe? Generally could change the where though like

UPDATE 'matomo_user_token_auth' SET 'last_used' = ? WHERE 'idusertokenauth' = ? and last_used < ?

It likely wouldn't make a difference though . We basically only want to update it when time() is higher. When value doesn't change then mysql should be smart enough though.

Maybe that's only one part of the issue. But firing thousands of updates on the same row isn't good in any case.
Will have a closer look at the code again later. Maybe there's any easy way to update it like only every 10 minutes or so

Be great to indeed only update it like every 10 min (in tracker and in general). Probably can't use general tracker cache as it would invalidate the cache every 10min when we use a much longer cache time on cloud.(1hr+)

@tsteur updated the PR. There will now always be an select to check if the last date for the token is older than 10 minutes. Not sure if that might make problems if multiple requests are executed at the same time