Testfor selected item?
Solution 1:
You don't need SelectedItemSlot when you can just use SelectedItem! Also probably because you were testing for an item named "key", not "Key2A".
/testfor @p[r=100] {SelectedItem:{tag:{display:{Name:"Key2A"}}}}
You don't need SelectedItemSlot when you can just use SelectedItem! Also probably because you were testing for an item named "key", not "Key2A".
/testfor @p[r=100] {SelectedItem:{tag:{display:{Name:"Key2A"}}}}