Getting the key cut, say, is no problem (4)
I believe the answer is:
easy
'no problem' is the definition.
(I've seen this in other clues)
'getting the key cut say' is the wordplay.
'getting' means one lot of letters goes inside another.
'the key' becomes 'e' (musical key).
'cut' indicates anagramming the letters (cut can mean mixed).
'say' with letters rearranged gives 'asy'.
'e' put into 'asy' is 'EASY'.
'is' is the link.
(Other definitions for easy that I've seen before include "Undemanding" , "Tranquil" , "Child's play" , "Soft" , "Effortless, uncomplicated" .)