Assuming you want to do this for a particular key, you can use liststreamkeyitems with 1 for the count parameter. This will give you information about the last item, include its block's Unix-style timestamp in the blocktime field. If you pass true for verbose you will also see the time the node first saw the item, in the timereceived field. If these timestamps are within the last 10 days, you'll know that the key was updated in that period. If they are earlier (or there is no matching item) then you'll know that it was not updated in that period.