As I already said, the value of the coin you have received is too low and it doesn't worth to use CPFP at all.
Do you really want to do CPFP and pay fee for a transaction in which you receive only 546 satoshi? Do you know that it's worth less than $0.2?

If you insist on doing so, you should make the CPFP transaction manually.
You should use coin control and select the the coin received in the unconfirmed transaction and another one to cover the fee.

Just note that coin control is available only on desktop version of electrum.