The thing is, the Miller-Urey experiment was never intended to recreate life, or anything close to life. It was very much a first step, showing that in theory, it was possible to create biological precursor chemicals from simple precursors that could have been available in an early earth's atmosphere. Since then, we've found dozens of other paths that can create those chemicals, and even found them on comets and other objects in space. Starting with a Miller-Urey experiment simply makes no sense.
Now, if the question is "If future god-like humans set up a planet with appropriate conditions for organic chemistry to begin, how long before you would get intelligent life?", we still can't give you a good answer, but at least the question makes more sense.
Judging by our sample size of 1, we can make some vague generalisations to get an approximation of an answer. First, we can assume that intelligent life would need to be multicellular. Without a multicellular structure, life is too small to build specialized organs like brains. On earth, it seems that the step from unicellular life to complex multicellular life was the most difficult step to take - it appears that simple multicellularity has evolved 40+ times, whereas complex multicellularity only seems to have emerged six times (animals, fungi, plants, and three kinds of algae), and only one of those lines is suitable for the development of intelligence.
The best evidence we currently have suggests that it took around 4 billion years for animals to evolve. After that, the first land life emerged relatively quickly, about 500 million years ago. From there, the emergence of intelligence is just a matter of evolution and some selective pressure tending towards big brains. On earth, that took at most 500 million years - we don't know if intelligence emerged at any time before us.
But this is just a sample size of 1, so any conclusions we can come to are extremely tentative and black-swannish. We don't know if earth was unusually well suited for intelligent life, or unusually hostile for intelligent life. We don't know if intelligence emerged many times on this earth before being wiped out by mass extinctions, or if we're unique in all the history of the world. (We can be reasonably sure that we're the first industrial civilization, for a variety of reasons).