The ASI reads through a line roughly parallel to the angle of incidence so if it still has airspeed in that direction it isn't stalled. If the AOA is exceeded the airspeed has bugger all to do with it. I think!
Jock will now kick my arse no doubt.
Yikes! It's a wee bit more complex than that particularly when you get to the edges of normal operational conditions (which a stall or spin is, of course). To keep the airframe 'flying' you need essentially non-turbulent airflow over the aerofoil surfaces. Wings, fuselage and tailplane/elevator. At a certain angle of attack (let's call it zero) the lift from the aerofoil surfaces equals the downward gravity force of the aircraft and load. As the aircraft gets heavier (more pax, fuel, baggage) the AOA needs to increase to match the downforce. That's fine all the while the airflow over the surfaces is essentially laminar. At some stage -- maybe low speed, an attempt to climb without power, engine output reduction (carb icing?) the airflow might become turbulent and the airframe approach a stall -- the pre-stall buffet due to non-laminar airflow. At this stage, in principle, the pilot can either push the stick forward to reduce the AOA, and increase airspeed or he can apply more power -- though the latter is dodgy if he is very close to a stall as he could end up in a power stall or power spin. It seldom happens presumably because it takes a bit of a clot to get into that position and clots don't often get licences? Darwinian principles tend to reduce the number of clotted pilots.