Overpair vs donk on the river

Grabbed by Holdem Manager
NL Holdem $0.05(BB) Replayer
SB ($5.02)
BB ($5.05)
UTG ($1.90)
UTG+1 ($5.05)
UTG+2 ($5)
MP1 ($5.22)
Hero ($5)
BTN ($4.93)

Dealt to Hero K♠ K♥

fold, fold, fold, fold, Hero raises to $0.15, fold, SB calls $0.13, fold

FLOP ($0.35) Q♦ 2♣ 3♦

SB checks, Hero bets $0.22, SB calls $0.22

TURN ($0.79) Q♦ 2♣ 3♦ 9♣

SB checks, Hero bets $0.57, SB calls $0.57

RIVER ($1.93) Q♦ 2♣ 3♦ 9♣ 8♣

SB bets $1.50, Hero ???

Villain is a 20/8 on 25 hands. A bit fishy, but not so terrible.

I think his line is so strong, I actually feared something like A♣Q♣ or Q♣J♣. But I wouldn't be surprised if he showed me 22,33 or 99 here. He would never lead so big on the river with KQ (and KQ is very unlikely since I hold two kings) or AQ; nor I think he would play a busted diamonds draw this way, he looks kind of passive so far.

So, is a fold reasonable here?