> Сейчас у меня есть мало времени

is correct as already pointed out.

In this sentence Genitive case stems from the relationship between the pronoun **мало** and the noun **время** and not from the verb **есть**.

So without the pronoun the case is Nominal as expected

> У меня есть время

However with the pronoun **мало**, which is the subject of the sentence, the Genitive form of **время -> времени** answers the question **(мало) чего?** - **(a little) of what?** 

Likewise with other quantitative pronouns **много, немного, немало, столько, несколько, сколько?**, also **чуть-чуть** and **полно́** which function as pronouns, and synonyms of those.