As far as I can see the prefix is not sufficient, a single non-digit character in the tail fails the conversion (and the equality check): http://3v4l.org/ctASF (vs http://3v4l.org/5FvJu, exact same strings but for the last character replaced by a digit)
Which means the probability of generating a hash value of the form 0[eE][0-9]{30} is (1/128)(10/16)^30 or 5.9e-9.
It certainly reduces the strength of the hash (and MD5 shouldn't be used anymore in any case), but still a roughly 6 in a billion chance of someone choosing e.g. a password and it happening to be exploitable in this manner.
The prefix is not sufficient though, the suffix must be entirely decimal otherwise it's not a valid number in scientific notation.