Unless it's keys then I play all day
You like them keys? We gon' play all day
He does, however, fuck around with keys—piano keys. Telling her they will play (fuck) all day.
And given how much he loves his drugs, this also means keys as in kilos of cocaine, which works with the next line.
Also, this could refer to a gangbang “game” where each person puts his keys in a bowl and a girl chooses keys at random. Whose ever keys she gets, she fucks.
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