But the IOC Refugee Athlete Scholarship-holder, a track and marathon athlete originally from South Sudan but now living in Kenya, is aiming for a second appearance.
His training plans ahead of the Tokyo 2020 Games in 2021 have temporarily been put on hold due to his training site, the Tegla Loroupe Peace Foundation, having to close during Kenya's coronavirus lockdown.
Speaking to World Athletics last year, Lokoro said: "Everything was about preparing for the Olympics, but now they are postponed. It is good in a way because it gives more time to improve. Now I must try to prepare for next year. For me, I hope I can be in Tokyo then."
Lokoro was born in 1992, and as a child worked on his family's cattle farm. He travelled to Kenya in 2006 to escape the Sudanese Civil War and join his mother, who had already fled to the Kakuma Refugee Camp in northwest Kenya two years prior.
He went to school and took part in sports in the camp, where he was spotted by the Loroupe Foundation in 2015.
That led to his Rio 2016 selection, and Lokoro took part in the 1500 metre track athletics event, finishing 11th out of 14 runners in his heat.
Following that outing, he took part in the World Athletics Athlete Refugee Team at the 2017 World Relays, 2017 Asian Indoor Games, 2018 World Half Marathon Championships, 2018 African Championships – where he reached the 1500 m final, and 2019 World Championships.
During the pandemic, Lokoro returned to Kakuma from Nairobi.
"There is no track here but there is open ground," he said to World Athletics.
"There is no venue where we can go. Everything has stopped for us. But we need to keep up our training, we need to keep our fitness.
"So that we are ready, so that we can achieve our goals when we have the chance."
And, possibly, we will see Lokoro in Tokyo as part of the EOR.