Should I have slow played here?

[olavfo]

Against the typical low limit lineup slowplaying isn't necessary, but this is the kind of situation where you could consider doing so (unraised pot, rainbow flop with no draws).

I usually bet the flop or try to get in a check-raise if I have a likely bettor to my left.

I think you played it fine, given your choice of plan. You can't fold, and putting in more raises seems like a bad idea, so just call down after Villains 3-bet.