You can use the Advertiser events tool to check if there is a postback from a specific click_id.
Go to Tools > Advertiser events > EVENTS.
Set the "Dates" for when the click must be sent to Aftrad and paste the click_id into the "Click event id" filter. If the click corresponds to a valid postback, you will see detailed information regarding it.
On the other hand, if there is no postback with that click_id in the selected "Dates", you will get an empty list:
