WD 40 won't hurt anything there, but it's not going to help anything, either. Plus, you want to keep that stuff far away from your finish. That it may not be kind to. If nothing else, it'll leave a nasty residue.
If it was me, I'd be pulling those screws out and replacing them, as they're very inexpensive. There's nothing unusual about them, so there's no point in investing any labor in them at all.
Just pull one and take it to the local hardware or fastener supplier, have them identify the thread, and get a handful. I'll be surprised if a box of 50 costs much more than a few bucks.