SUMPRODUCT Contains Text, Using Asterisk

Let's say I have two columns: Homeless (column A) & Services (column B). Homeless responses can be either "Y" or "N". Service can be "a", "b", or "ab". Here is an example:

Homeless Service
y a
y b
n a
y ab

I was hoping to use SUMPRODUCT to calculate clients who are homeless and receiving "a" service. I want to be able to calculate those receiving "a" service even if they are receiving "b" service, so I attempted to use asterisks like I have used prior with the COUNTIF function. Here is what I thought would work:
=SUMPRODUCT((A2:A5="y")*(B2:B5="*a*"))

And I expected it to return 2, but I found that I couldn't get the SUMPRODUCT to work with asterisks. I am able to get the results I want be creating a new column to sort the services into just those who are homeless and then using COUNTIF, but I'd rather come up with a more streamlined approach.