Hi Wolfbane, welcome to the forum!
It is certainly possible, and it has it's benefits, but I don't think that speed will be improved.
I've done some tests some time ago (might not be the current version) with LuaSQL and it looked rather slow to me compared to writing to a file.
I'll have a test again soon to see if that's still the case, if it's fast enough an option could be added to store stuff in MySQL instead of files.
I want to keep the option to store stuff in flat files, because most Windows hubowners don't have a MySQL-database running. And since ease of use is a key issue for the development of Flexhub, I don't want to force owners to install MySQL to be able to run Flexhub.