> in a single lifetime
There’s some wiggle-room there. A species that is naturally biologically immortal (or had biology that supported long periods of inactivity) might not find that spending hundreds of years to travel to a nearby star system was a deal-breaker for interstellar travel. They might be more motivated to execute such a project than we are since they could not just wait for their ancestors to die of old age as a way for younger members of the species to have control.
Also there is a possibility that a species might develop the technology to create a partly or fully artificial version of themselves that makes long interstellar trips less of an obstacle (synthetic biology, a combination of biology and machine, pure machine, etc).
Natural humans are certainly poorly suited for interstellar travel, but it may be that other kinds of life are more tolerant of it, or have redesigned some members of their species to handle it.