Biologically modern humans have existed for around 2-300,000 years or longer. Modern hominids with culture and tool use such as denisovans and cro magnon extend this timeline further.
Additionally, consider that complex organisms with human like intelligence may have existed in the deep past (perhaps arising from octopoid or reptilian species) and such a presence would be invisible to the archeological record (or have simply evaded it.) Such a species could have followed a different technological path, making tell-tale techno signatures like nuclear isotopes and carbon emissions unable to detect them today.

Consider that human civilization went from their peak industrial capability being horse drawn hoes to nuclear power in under 100 years. Determine the percentage possibility of the likelihood that an organism, human, hominid or otherwise achieved a civilization with parity to our own in complexity (perhaps not in industrial terms that are recognized by use today.) Keep an open mind and try to see past doctrinal thinking and assumptions, with the awareness that virtually all scientific facts about the history of our planet, its geology and evolution from 40-50 years ago we took as truth have been proven wrong. Lack of evidence is again expected in this exercise. Use logic instead of evidence. Consider that a civilization could achieve technological progress on different avenues; e.g. tapping into geologic energy sources, bridging the charge gradient between the earth's surface and ionosphere, etc. These approaches would allow massive leaps in capability up to interplanetary travel without industrial impacts on the biosphere. Indeed, such a civilization would logically inherit a different attitude about the utilization of natural resources making them more difficult to detect today. Consider also the nature of cataclysmic cycles and concede cataclysms occur much more frequently than we have historically considered.