Small-time? (6)
I believe this is a double definition.
'small' is the first definition.
(similar in meaning)
'time?' is the second definition.
(sixty seconds)
(Other definitions for minute that I've seen before include "Precise" , "Tiny; written note" , "barely noticeable?" , "Little -- 60 18 across" , "Tiny - proportion of time" .)
'small-time' is the definition.
(I've seen this in another clue)
This is all the clue.
(Another definition for penny ante that I've seen is " small stakes".)