Aspect ratio affects the induced drag. CDi=Cl^2/(Pi*AR).
At lower (indicated) airspeed we have a higher lift coefficient so higher induced drag. The greater the aspect ratio the lower the induced drag at a given lift coefficient. However, the higher aspect ratio wing is always going to be heavier, all other things being equal. Ultimate lift coefficient is probably going to be worse too as it tends to varey with the Reynold number.
So in real life we tend to find really high aspect ratio wings on gliders which need to have a good performace, measured as lift/total drag, at low airspeeds and in long range aircraft, eg Canbera, U2, B52..