PowerApps retrieving data from SQL using compound criteria

I feel as if I must be misunderstanding something basic, here. I admit I am a little baffled.

In PowerApps, I can generally get LOOKUP to work if I have a single item as part of my criteria.

But I am having the darndest time getting multiple criteria to work.

The TLDR version: How do I format a PowerApps command (I presume LOOKUP) using multiple items as criteria to give me a proper output.

My database table design:

My database sample data:

And the two different ways I've tried building my LOOKUP query (both of which produce blank results):

My expectation was that the query would produce the answer "LS57CG954" (which is the only serial number sharing those two criteria).

How do I get this?

minor note 1: Although my sample table is small, the formal table will contain something on the order of 60,000 rows. There are about 13,000 unique Store_Number values, and for each Store_Number, there are from 0 to six different entries, based on Install_Position. There is never the case where two devices occupy the same position in the same store.

Okay, that took me way longer than expected, but this is what solved it without delegation warnings...

Basically, I used the IN operator. I reasoned that maybe there were invisible characters in my database strings, or maybe there were weird tweaky ways in which strings were being handled between these two. Using IN bypassed a lot of those issues.

Whatever the case, this is the construct that gives me exactly the data I'm looking for:

Set(TextValue,LookUp(DTT_Monitors,"S00666" in Store_Number && "OSB" in Install_Position,Serial_Number));

May it help you in the future!