When I create an API client connector with clicking on Edit/Review and providing some changes, in my case changing the name and type of api_key to HTTP header and name: "test". The name change is ignored.
The same went for adding a query parameter for me, it is present in the UI but isn't actually sent to the application from what I saw.
I am including an export of the integration, if you find "test" you'll eventually find apikey with name test and if you look for "asdf", you'll find a parameter in query, but actually if you run the integration nothing is sent to the REST service.
Using this API specification: https://petstore.swagger.io/v2/swagger.json, where the api_key security specification is already defined, so needs to change.