Key shone out when picked (6)
I believe the answer is:
chosen
'picked' is the definition.
(I've seen this in another clue)
'key shone out' is the wordplay.
'key' becomes 'c' (musical key).
'out' indicates an anagram (out can mean wrong or inaccurate).
'shone' with letters rearranged gives 'hosen'.
'c'+'hosen'='CHOSEN'
'when' acts as a link.
(Other definitions for chosen that I've seen before include "If you're one of these few, you're very privileged" , "Select" , "Selected, preferred" , "Selected - Japanese name for Korea" , "part of Asia once" .)