getKey(54)
Ans*(Ans≠K)
If Ans
Then
Ans→K
<<More code>>
End

That is the best I can think of, sorry.

What I do, is store 0 to K, and then at the start of a Repeat loop or whatever, the first line is "If K=0:GetKey->K:End".  That way, as long as K has some value, it makes sure you read it before it checks any other keys.  And to acknowledge you read it, just write 0 to K.  This works because it won't read getkey again until you tell it to.  It has the added benefit of letting you decide if the users should be able to press the key again, or shouldn't be able to press keys.  Like storing 1 to K automatically disables key presses.  Or if you want, you can make the person continue to go right for 5 steps, but keeping a counter, and storing 0 to K when the counter is up.

Alternatively, you can use this piece of code and eliminate one of the getKeys()

If getKey(54)
If K
...
End
0->K
Else
1->K
End

0->A
.Some sort of loop
If A
... Stuff that should only be run w/o repeat
End
...stuff with repeat
getKey=0->A
.end loop

This could be a relatively efficient solution.