Keen to see the Queen over time (5)
I believe the answer is:
eager
'keen' is the definition.
(I've seen this before)
'the queen over time' is the wordplay.
'the queen' becomes 'ER' (Elizabeth Regina).
'over' indicates putting letters inside.
'time' becomes 'age' (an age is a period of time).
'er' placed around 'age' is 'EAGER'.
'to see' acts as a link.
(Other definitions for eager that I've seen before include "passionate" , "Fervent" , "Whole-hearted" , "willing" , "Low platform" .)