Non-union workers are out of it - the store is shut (6,4)
I believe the answer is:
closed shop
'non-union workers' is the definition.
'closed shop' can be an answer for 'workers' (I have seen 'Exclusive workers' mean 'closed shop' so perhaps 'workers' could also mean 'closed shop'). I'm not sure about the 'non-union' bit.
'out of it the store is shut' is the wordplay.
I cannot really see how this works, but
'of' could be 'o' and 'o' is found within the answer.
'it' could be 'e' ('e' can mean 'electronic' which is similar to 'IT') and 'e' is located in the answer.
'store' could be 'shop' (synonyms) and 'shop' is found within the answer.
This explanation may well be incorrect...
'are' is the link.
Can you help me to learn more?
(Other definitions for closed shop that I've seen before include "only the unions were taken in" , "Exclusive workers" , "Ceased trading" , "where union holds sway" , "Where union membership is required" .)