If villain is really loose on all streets then a call is fine here, he can be doing this with A Xs and some other hands but prepare to lose some of the time. There is a difference though between a player that is very loose pre flop and very loose/calling station/over aggro on every street, often winning players can be loose pre flop as there post flop skill gives them an edge.
Also with KxKs on that board I am c betting almost every time, what was your reason for checking? I prefer not to give up the lead on the flop as you are already at a disadvantage being OOP.
Personally I make it like $45 with a flat caller to the original raise pre. If the original PFR calls the CO gets great odds
at $31 and if he's as loose as you say Id charge him more anyway as he's probably calling.
Would be interested to know what the end result was? As I say this is really player dependant.