Put loc: in front of the coordinate, like this -
https://maps.google.com/maps?q=loc:-25.454435,-49.33136
Here's what you get -

When you don't use loc:, Google shows the nearest possible place for the convenience of the user as it's a random point. But when you're using loc: Google knows that you are looking for just the location of the point, nothing else.
Update:
If you want to show a info bubble on that certain coordinate, you can also do it this way -
https://maps.google.com/maps?q=LocationName@-25.454435,-49.33136&iwloc=A
Here it'll point to that certain location with a red marker A and you can set information about it inside a info window + with iwloc, you can say that it needs to show the info to the red bubble marked A. Output -
