Yeah I would fold aces if they were 48% against kings and 56s except:

1,370,754 pots with board cards: (unspecified)

AcAs KhKd 5s6s
% chance of outright win 60.904582 17.726740 21.082485
% chance of win or split 61.190775 18.012933 21.368677
expected return, % of pot 60.999980 17.822138 21.177882
fair pot odds:1 0.639345 4.610999 3.721907
pots won: 836159.67 244297.67 290296.67

1,370,754 pots with board cards: (unspecified)

AcAs KhKd 5h6h
% chance of outright win 61.159916 17.471479 21.082485
% chance of win or split 61.446036 17.757599 21.368604
expected return, % of pot 61.255290 17.566853 21.177858
fair pot odds:1 0.632512 4.692539 3.721913
pots won: 839659.33 240798.33 290296.33

There, you're a 61% favorite. Again, no reason to fold.