Stats on SB?
Is he passive, or aggressive?
The thing is, K5o is not a strong hand, and it's not even ahead of a 60% opening range.
Against a lagtard, you'd be better to just call preflop, and against a regular fish, you'd be better to just fold preflop.
On the flop, neither a lagtard nor a fish is going to go away easily, especially on that type of board, so this will rarely work.
This would actually work better against a solid opponent. But is a solid opponent going to donk this flop with anything you can push him off of?
Wrong spot to do this in, imo. I think you got lucky.