Lockout Lego on after going down a flight of stairs
It is highly unlikely that you have damaged your suspension.  At worst you may have shortened its life by some small and immeasurable amount.

As long as it functions okay now, all you need to do is remember to service it at the appropriate interval.

You can't possibly damage locked-out suspension by riding on flat smooth road because that's exactly what its designed for.    Hopping and stairs would be the cause of any damage.