She completed the course in two minutes and 15.79 seconds.
"I think this is not my last Olympics, I hope to have a long career," said Maļuka.
The best 16 out of 34 swimmers qualified for the semi-finals.
This is Maļuka's second Olympics. Three years ago in Tokyo, she placed 24th in the 200-meter freestyle and 37th in the 100-meter freestyle.