In both expressions, "this" is an alternative to "these". "At" pinpoints locations in time. "In" describes intervals in time. Use "in" for action that emerges during a sustained interval. Here are examples: "In times like these, when it is difficult to find a job, many young people choose to live with their parents." "In" is better because such periods can last for years. "At times like this, when I catch a cold, I drink orange juice and swallow vitamin C pills."

There's really no difference, you can use whichever you like and they mean the same thing!