Realism is about the assumption that there are observer independent "truths" or "mechanisms" underlying or causing the phenomena of reported "states of affairs".
In my book, what you describe is positivism: the belief that there are positive (objective, absolute) laws organizing the universe, and that science can discover them all, given enough time. Positivism is indeed a realist philosophy, but a very idealist one in fact, since the Logos rules the Cosmos.
Many other forms of realism exist, in which reality may not be fully organized or organizable through natural laws, and may retain a part of chaos.
Realism only assumes that there is some stuff out there, which presence is observer-independent.
When you lost your keys, they are somewhere. They haven't gone poof into thin air. Whether you remember where you put them or not, whether you understand how they work or not, or whether you appreciate their intricate atomic structure to its full extent or not. The darn keys are still there somewhere... That's what realism says. So if you're looking for your keys when you misplaced them, you're a realist.