Patience: second magical creature's getting key (4-7)
I believe the answer is:
self-control
'patience' is the definition.
(thesaurus)
'second magical creature's getting key' is the wordplay.
'second' becomes 's' (common abbreviation).
'magical creature' becomes 'elf' (creature in fairy tales).
'getting key' becomes 'control' (I am not sure about this - if you are sure you should believe this answer much more).
's'+'elf'+'control'='SELF-CONTROL'
Can you help me to learn more?
(Other definitions for self-control that I've seen before include "Entice" , "Willpower" , "Composure" .)