Franchise (also called suffrage) is the specific political term for the right to vote and to be voted for in an election. It encompasses both active franchise (the right to vote) and passive franchise (the right to stand as a candidate for election).
While the right to vote is indeed a constitutional right in most democracies (it is guaranteed under the Nigerian Constitution, for example), the precise political science term for this specific right is franchise. "Constitutional right" is a much broader category that includes many other rights such as freedom of speech, right to life, and right to property - it is not specific enough to describe the right to vote and be voted for.
"Election right" is not a standard term in political science. "Inheritance" refers to the passing of property or titles from one generation to another and has no connection to voting rights.
In Nigeria, franchise is subject to certain qualifications: a citizen must be at least 18 years old to vote and must be registered with the Independent National Electoral Commission (INEC). Age requirements for standing as a candidate vary by office.