No search engine is refreshing every website every minute. Most websites don't update frequently, and if you poll them more than once every month, your crawler will get blocked incredibly fast.

The problem of being able to provide fresh results is best solved by having different tiers of indices, one for frequently updating content, and one for slowly updating content with a weekly or monthly cadence.

You can get a long way by driving he frequently updating index via RSS feeds and social media firehoses to provide singnals for when to fetch new URLs.