Getting protein FASTA sequence based on keyword with python
Found what I was looking for. In:

searchResultHandle = Entrez.esearch(db="protein", term="terminase large", retmax=1000)


I've added:

searchterm = "(terminase large subunit AND viruses[Organism]) AND Caudovirales AND refseq[Filter]"
searchResultHandle = Entrez.esearch(db="protein", term=searchterm, retmax=6000)


which norrowed down my searches to the desired viruses. Granted it's not filtered by host, but by a taxonomy group, but it is enough for my work.

Thank you @Llopis for additional help