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.