The searching speed depends on your subscription plan and the category's filter you applied to the search.
While starting Scout Job you'll see the estimated amount of items and approximated time of the search.
In Bussines and Ultimate plans, you can choose the Searching method: fast, normal or deep.
Fast method search in bulk ASINs by UPC, EAN. This is the most powerful and accurate method.
Normal method search ASIN by UPC (if they are) and then by product name, part #, SKU and a lot of more if ASIN by UPC weren't found.
Deep method search ASIN by UPC (if they are) and then by product name, part #, SKU and a lot more even if ASIN by UPC was found.