I would like to know what translation you are using, because without exception, every translation I have seen uses either the subjunctive form or future tense. I have yet to see one that uses indicative present tense.
NIV: "whoever believes in him shall not perish but have eternal life"
KJV: "whosoever believeth in him should not perish, but have everlasting life"
CJB: "everyone who trusts in him may have eternal life, instead of being utterly destroyed"
MSG: "by believing in him, anyone can have a whole and lasting life"
RSV: "whoever believes in him should not perish but have eternal life"