How to Create a Query Data store API with POST Method

I have an API with Query Data store, when i test it using GET method it works fine, but it's parameter must be present in url, because the parameter is user and password, i think it is not wise to use GET method, so i tried to create a similar API but instead of GET method, i used POST method, but it always return an 404-Not Found response when i try it out using SOAPUi.
My question is, how to create an API that can be accessed using POST Method and the parameter can be inputted in the body of the request not in the url? Or all Query Datastore API can only be built using GET Method?

Thanks.
Regards,

Julianto

OriginalPostID-252869