How to optimize webjob triggering from service bus queue to not use high cpu

Question

I have webjob in azure which gets triggered from service bus queues. It has batch size of 100 and utilizes high cpu approx 90%. Need help how to make it 50%

I added cache and implemented lock so that all thread dont hit db and once one thread gets data from db and fills cache other threads get data from cache and apply where filters and return

Still no improvement