PokerStars No-Limit Hold'em, $0.02 BB (7 handed) converter

Hero ($3.10)
SB ($1.29)
BB ($4.98)
UTG ($9.74)
MP1 ($1.92)
MP2 ($6.42)
CO ($6.70)

Preflop: Hero is Button with A, J.
UTG calls $0.02, MP1 calls $0.02, MP2 raises to $0.04, 1 fold, Hero raises to $0.1, 1 fold, BB calls $0.08, UTG folds, MP1 folds, MP2 raises to $0.3, Hero calls $0.20, BB folds.

Flop: ($0.75) A, 7, T (2 players)
MP2 bets $0.3, Hero calls $0.30.

Turn: ($1.35) 2 (2 players)
MP2 checks, Hero checks.

River: ($1.35) Q (2 players)
MP2 bets $0.5, Hero ???

My read was that he was on AK because he had shown only premium cards to this point.
Is this a situation in which you always call because you can never be that sure he has a kicker better than J?