Cracking MD5 of 270 length plain-text -partially know-

[mdi]

You're not going to be able to use any optimized hash cracking application for this (especially not hashcat), you'll need to use or write a cracker with a generic multiblock MD5 implementation from e.g. OpenSSL or something.

Thank you for your answer. I've build my own basic python script which is works without any issue but yea I would like to use optimized hash cracking app.