Filtering data by key value

I can’t figure out how to limit data only by key value. Let’s say I have following data:


How to query this data by key value so I get only objects that I need. For example I would like to get only object with key “b” of value “XYZ1” - it should return me only second object.

This endpoint!/addresses/getDataItem_1 is able to filter only by key name but I need to filter data by key value.

Write a script/piece of code to do this?