The African side were bowled out for just 93 in the 44th over with Morris Ouma top-scoring with 39 while Rakep Patel, with 18, was the only other batsman to reach double figures.
Slow left-armer Hamza Hotak was the leading Afghanistan bowler, claiming 3-19 off his 10 overs.
Victory will secure second place for Afghanistan in the World Cricket League (WCL) Division One and guarantee a spot in the 2015 World Cup in Australia and New Zealand.
But should Kenya stun the heavily-favoured Afghan side then the UAE, who have finished their programme, will qualify instead alongside runaway WCL winners Ireland.
Afghanistan, who were playing in the World Cricket League Division 5 in 2008, had the momentum leading up to Friday’s clash, having won five consecutive 50-over matches.
In Monday’s Twenty20 International against Kenya, they won by 106 runs and carried that form through to Wednesday when they romped to victory over the African side by eight wickets in the first of the two determining ODIs.
Then, Kenya were dismissed for just 89 with Afghanistan reaching their target inside 18 overs.