Punithan Genasan, 37, received the sentence on Friday for his role in a drug deal that took place in 2011.
It marks the city's first case where such a ruling has been done remotely.
Human rights groups argued that pursuing the death penalty at a time when the world is being gripped by a pandemic was "abhorrent".
The vast majority of court hearings in Singapore have been adjourned until at least 1 June, when the city's current lockdown period is due to end.
Cases which have been deemed to be essential are being held remotely.
"For the safety of all involved in the proceedings, the hearing for Public Prosecutor v Punithan A/L Genasan was conducted by video-conferencing," a spokesperson for Singapore's Supreme Court told Reuters.
Mr Genasan's lawyer, Peter Fernando, said his client is considering an appeal.
Singapore has a zero-tolerance policy for illegal drugs. In 2013, 18 people were executed - the highest figure in at least two decades, according to Amnesty International.
Of those 18, 11 had been charged with drug-related offenses.