"Τουλάχιστον θα μπορέσεις να έρθεις."
Translation:At least you will be able to come.
Yes, the word "can" is normally present tense, but "at least you can come" is talking about the future. For example, you can say "at least you can come tomorrow."
If you were talking about the present, you would say "at least you could come" or "at least you were able to come" (which could also be about the past).