The revivify spell has a fixed cost, but it doesn't have a specific saving throw to resist it; neither does it reference a "willing creature", as the resurrection spell does.
Assuming my players have the resource to cast revivify on a recently killed enemy, can the creature refuse to come back to life knowing that he will probably be interrogated and maybe tortured?
The target isn't specified by the spell's wording or any general rule to need to be willing. Therefore it works on unwilling targets too. The omission is particularly telling because, as you yourself point out, the similar spells Resurrection and True Resurrection have a wording to specify that the target has to be willing but Revivify has not.
It seems unlikely that Revivify's wording is that way by accident, given that the spell has been changed in the errata while still leaving the willingness requirement out.
On DMG page 24, under "Bringing Back the Dead", it states that you cannot bring back the soul of an unwilling creature:
A soul can’t be returned to life if it doesn’t wish to be. A soul knows the name, alignment, and patron deity (if any) of the character attempting to revive it and might refuse to return on that basis. For example, if the honorable knight Sturm Brightblade is slain and a high priestess of Takhisis (god of evil dragons) grabs his body, Sturm might not wish to be raised from the dead by her. Any attempts she makes to revive him automatically fail. If the evil cleric wants to revive Sturm to interrogate him, she needs to find some way to trick his soul, such as duping a good cleric into raising him and then capturing him once he is alive again.
