Based on an article written by Healthline, there are some zinc-rich foods that men should regularly ingest in their 40s and above to boost their sperm quality.

Because the cells that produce sperm in males slowly decline in their capacity to make sperm that are of high quality due to the ageing process that slowly activates and becomes more apparent as men advance in old age, but regular ingestion of zinc-rich foods will keep the cells active and fit to produce the right quality of sperm in the bodies of men who are at their ages of 40 and above.

The zinc-rich foods are discussed briefly in the following paragraphs below.

When considering the list of foods that are rich in zinc that men who are in their 40s and above can consume regularly, spinach will no doubt be on the list because its cells are properly loaded with a high proportion of zinc, organic compounds, and other vital minerals that when ingested, go into the bloodstream and are transported to the body cells that utilize them for themselves and for boosting quality sperm production.
Beans contain a decent amount of zinc that is enough for the body cells in charge of sperm production, and other nutrients like antioxidants and vitamins also play their part in assisting these cells in destroying toxins called free radicals that can interfere with their work and cause them to underperform in making sperm of low quality.
Chicken is one healthy food that contains a lot of zinc, vitamins, and proteins that are good for the body and, most importantly, for the production of quality sperm.

However, you should avoid ingesting too much fried chicken or the ones seasoned with chemicals that give it an aroma or flavour, because they can badly affect the body and sperm producing cells.

Instead, eat boiled chicken seasoned with garlic or onion and a little salt in moderation.