That is the key you want, then. Didn’t you already test it out sucessfully?
For example, to calculate 4[sup]7[/sup], press 4, then the key, then 7, then enter
Oh, come on. It is either
4 <enter> 7 y[sup]x[/sup]
or it is
4 y[sup]x[/sup] 7 =
– algebraic-format calculators do not have an “enter” key.
But I do have the keys I need, as I noted upthread. 
Of course, there are a wide variety of smartphone calculator apps, even free ones. I use one that emulates an HP48.