Right key starts to unlock everything - salvation! (6)
I believe the answer is:
rescue
'salvation' is the definition.
(thesaurus)
'right key starts to unlock everything' is the wordplay.
'right' becomes 'r' (common abbreviation).
'key' becomes 'esc' ('Escape' key on a computer keyboard).
'starts to' suggests taking the first letters.
The first letters of 'unlock everything' is 'ue'.
'r'+'esc'+'ue'='RESCUE'
(Other definitions for rescue that I've seen before include "gets one out of a tight corner" , "Salvage" , "delivery" , "Set free from harm and evil" , "Free from danger or captivity" .)