FR50 AKs

Hand converted with online PokerStrategy.com hand converter:

Play hand

$0.25/$0.5 No-Limit Hold'em (8 handed)

Known players:
[tg]UTG2$53.75:///////;MP1$51.60:///////;MP2$26.62:///////;MP3$55.04:///////;CO$36.94:///////;BU (Hero)$64.04:///////;SB$18.00:///////;BB$54.43:///////;[/tg]

Preflop: Hero is BU with A:s, K:s.
4 folds, CO raises to $1.25, Hero raises to $4.00, 2 folds, CO calls $2.75.

Flop: ($8.75) 9:d, A:c, 7:s (2 players)
CO checks, Hero checks.

Turn: ($8.75) 6:s (2 players)
CO checks, Hero bets $5.00, CO calls $5.00.

River: ($18.75) 5:d (2 players)
CO bets $27.94, Hero ???

Villain is a doubled up MSS

16/13/3.5 AF over 6k hands

fold to 3bet 67%

WTSD 30% wins 47%

I didnt bet the flop thinking well there is nth much he can call here anyway.

the river shove indicates a flopped set? or rivered straight? or maybe a missed draw

Should I call here?