You can't use substitutions inside of substitutions. To have what you're wanting you'll need to use a CB Query Field to calculate the date difference of your field to NOW() then output a 1 if it's greater and a 0 if it's not. Then in your IF statement you'd compare against that CB Query Field. Below is an example query and IF statement of this usage.
Title: cb_subscribed
Query:
Code:
SELECT IF( DATEDIFF( `cb_memberexp`, NOW() ) <= 0, 0, 1 ) FROM `#__comprofiler` WHERE `id` = '[user_id]'
The above takes the difference in days between cb_memberexp and current datetime. It then checks if that value is less then or equal to 0 meaning expired. If it is expired it returns a 0 and if it's not it returns a 1. You could then use the above CB Query Field in the below IF statement.
[cb:if cb_subscribed="0" ]EXPIRED[/cb:if]