Taken from a Spigot comment:

Perhaps something to take into consideration.
Doing a query one time per second (or even 10 times per second) on a table that has nothing more than the timestamp of the latest update would cost next to no server resources as databases would simply cache this result. Once an update is found LuckyPerms could load the entire config. This would make configuring servers easier. Just point to the central database and enable global configs. If someone edits something on any of the connected servers, things could get propagated automatically almost instantly