[Closed] NL10 - KK facing donk push on the river

Cassava Poker $0.05/$0.10 No Limit Hold'em - 8 players - View hand 1418714
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MP2: $1.79
Hero (CO): $15.85
BTN: $10.00
SB: $2.45
BB: $4.23
UTG: $11.57
UTG+1: $5.00
MP1: $10.14

Pre Flop: ($0.15) Hero is CO with K K
2 folds, MP1 calls $0.10, 1 fold, Hero raises to $0.50, 3 folds, MP1 calls $0.40

Flop: ($1.15) 5 T 6 (2 players)
MP1 checks, Hero bets $0.96, MP1 calls $0.96

Turn: ($3.07) 3 (2 players)
MP1 checks, Hero bets $2.50, MP1 calls $2.50

River: ($8.07) 7 (2 players)
MP1 bets $6.18, Hero folds

Villain was a super fish / calling station playing 79/0 with aggression factor 0.4 over 631 hands.

Considing he could really have anything I don't even bother putting him on a range. Pocket AA and 73o equally likely

I value bet big flop and turn to protect and giving me the opportunity to push river if check to. But considering his very low aggression and pushing the river I think my overcard is nver good here, correct laydown?