You cannot compare a MCA with a bachelor's degree and no one would do so. Please check the eligibility criteria once more , it would mean 55% marks in the bachelor's honors graduate exams.
I do not know the particulars of your BA/BCA. Bachelor's degree in practical terms is equated to a regular/ordinary pass and honors in some countries where it is practiced has more weightage, more academically stronger and hence a better choice for teaching, research and pioneering work related employments. In some courses, honor's degree takes a year more. Honor's also have a subject of specialization, that the regular degree does not have.
If the advert says 55% in a honors graduate exam, you cannot compare MCA because its a masters/post graduate degree.
In your position, I would apply stating all the true facts and leave the decision to the Government recruitment company rather than trying to read too much and not apply. As long as your stated facts are true, at the most, your application would be rejected but you wouldn't know unit you apply.