The OPS/MVS API field API.TOKEN does not contain the value from the THREAD-TOKEN field that is part of the THREAD-STATS record, Ifcid 148.
As described in the product documentation, section "Exception Action to Notify CA OPS/MVS", this field "Specifies a unique value for the instance of an exception for a data collector". It is a way of uniquely identifying the instance of the exception to the OPS/MVS environment.
If you wish to cancel the thread, it is recommended you use the option on the Exception Actions Part 2 screen to issue the PTT command to Cancel a thread. You can include the &ACEXXXX exception variable field in the PTT command text to ensure a specific thread is cancelled.