Line Item Product Search

All I added a custom field to products for “Discontinued” and would like to exclude all products marked as such from any search. When in the Quotes module and adding a new line I am looking to update this SQL query of the product lookup.
To be clear if adding a new line and I type “AM-1” and there are two products AM-100 and AM-101 and AM-100 is Discontinued I don’t want it to show up in the pop up text box search to choose from.

Any help would be greatly appreciated!