I think there is plenty of fold equity here. Over pairs make decent bluff catchers on this river but most of villains OPs will contain spades after call/ call line making it harder for them to hero call, same goes for KQ/ AQ type hands.
It does not look like you hit the flop or the turn. Calling you down with AA or KK then folding the river doesn't seem right to me. I think the only reason to bet is to get him to fold a better Q that also has a spade draw.