Salesman in Florida working at top speed (4,3)
I believe the answer is:
flat out
'at top speed' is the definition.
(working flat out is working fast)
'salesman in florida working' is the wordplay.
I cannot quite see how this works, but
'florida' could be 'fla' (abbreviation) and 'fla' is found in the answer.
The remaining letters 'tout' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for flat out that I've seen before include "At top speed; intense (effort)" , "KO'd" , "At top speed - totally exhausted" , "Lying on floor" , "very quickly?" .)