Pretty tough and interesting spot actually, I agree his sizing is rather large here but I believe you can still call the flop and reevaluate the turn. It's a tough spot because even Nl20 regs know that you are going to be quite strong here.
His raise size is super strange because it leaves him with 15$ effective behind and if you call flop. The pot on the turn is going to be 10.3$. I'm not sure what level guys are on at this stake but I think the better regs will think about what sizing sets up a good stack to pot ratio with their value hands but will ignore this with their bluffing hands. As well as whether they want to go with a 3 street plan or two street plan. This sizing sets up neither , unless he 1/2 pots turn,1/2 pots river which seems strange on a drawry texture. (This maybe totally wrong and they just do w.e
)
What are the population tendencies you have noticed in this spot? Are people only raising sets and combodraws? I haven't played Ipoker in awhile but I do remember lots of regs being very spazzy. Either way I would still call the flop.
IMO there are two ways to look at his large raise size:
1) He is not bluffing very often because he thinks you are not capable of folding overpairs. Therefore he is going for immediate value with his sets.
2) He believes you are capable of folding over pairs or he thinks you fold too much to flop raises and takes a bigger size to scare you off.
To me it looks like option 2.
You should also look at his turn and river stats (even with a small sample). It will give you an indication as to whether he gives up with his bluffs or plays them very aggressively.
If you think it's option 1 and his turn and river stats are passive, you can fold if he bets turn. Since he probably just gives up all his bluffs once you call.
If it's option 2, I would call the flop and think about jamming some turns to rep a combodraw or if he is aggressive and you think he is going to triple barrel bluff, then just call down.
I don't think 3 betting the flop is very good here because you don't let him continue with his bluffs and are probably only getting called by better hands. Plus your hand plays very well a bluff catcher. But I'm also undecided on if the K :heart:, makes our hand better or worse for bluff catching. 
These are my thoughts, I would be interested in hearing someone else is opinion.