using session variable inside jsonPath

Am i able to use a variable like the current time inside a jsonPath expression.

Say i call an api which returns a list of JSON elements

{classes: [ {"name":"maths", "start":'2017-02-15:17:00:00'}, {"name":"science", "start":'2017-02-15:18:00:00'} ]}

i want to find the classes that are after 2017-02-15:17:30:00

which i can write as

`

.check( jsonPath( "$..timeSlots.[?(@. start > 2017-02-15:17:30:00)] ).saveAs("class") )

`

but what if i wanted find the classes that are after now?
can i do something like?

`

.check( jsonPath( "$…timeSlots.[?(@. start > ${now})] ).saveAs(“class”) )

`

where “now” is a session variable… Or do i need to do this as predicate/filter out side the jsonPath

thanks