Since you want to do it quickly the option will be to delete all the queued process flow in the table AU_PROCESSQUEUE inside the Adeptia Backend database and in the table AU_TRANSACTIONDATA inside the Adeptia Log Database.
To get the information of the queued process flows from table AU_PROCESSQUEUE try executing the below query on your backend database:
SELECT * FROM au_processqueue WHERE au_status = 'Queued'
To get the information of the queued process flows from table AU_TRANSACTIONDATA try executing the below query on your Log database:
SELECT * FROM au_transactiondata WHERE au_activitystatus = 'Queued'