As a completely seperate way to do this, if it's ok that any
updates to a row make it considered the 'last inserted',
you can add a new column to your table of type
TIMESTAMP, and mysql will keep it up to date as the most
recent insert or update to that row. You could then select
on that, and it'd be ok if it's from a separate session.
Hope this is at least interesting, and maybe helpful :)