Bulk Delete of completed system jobs stuck

I have a CRM On Premise with 2015 installed.

Looking at the database there are about 6m records in the AsyncOperationBase table and 16m in the WorkflowLogBase table which seem to have been generated from a single workflow running (I've since set it to delete completed system jobs!)

I have started a bulk delete job from the CRM but it's been stuck as In Progress with 0 records deleted or failed to delete for 3 hours.

Is it ok to delete records from the database using the following statements without running the cleanup script?

DELETE FROM dbo.AsyncOperationBase WITH(NOLOCK) WHERE StatusCode = 30 AND OperationType = 10;

DELETE FROM dbo.WorkflowLogBase WITH(NOLOCK) WHERE Status = 2;

I have read this article but I fear it will clear the whole tables rather than just the records from the single workflow

https://support.microsoft.com/en-us/kb/968520