cron.schedule() running multiple times:

Question

I have this function which is used to check every second if the current time matches the time of a scheduled email using cron.schedule. However, when it reaches the right time the sendEmail function runs 20+ times as well as the sql query all within a second.

the emails array is structured like this: [[time, address, subject, message, id], [time, address, subject, message, id]...]

code:

function send() {
  for (let i = 0; i < emails.length; i++) {
    let emailTime = emails[i][0];
    let recipient = emails[i][1];
    let subject = emails[i][2];
    let message = emails[i][3];
    let emailId = emails[i][4];

    if (emailTime.split(' ')[1] == '24') { // cron only supports hours 1-23
      let emailTimeSplit = emailTime.split(' ');
      emailTimeSplit.splice(1, 1, '1');
      emailTime = emailTimeSplit.join(' ');
    }

    cron.schedule(emailTime + ' *', () => {

      sendEmail(recipient, subject, message); //asnychronous function in another script

      var sql = `DELETE FROM emails WHERE email_id=${emailId}`; 
      con.query(sql, function (err, result) { //deletes email details from sql table 
        if (err) throw err;
        console.log('items removed!');
      });
    });

  }
}

setInterval(send, 1000);

I tried removing removing the email from the emails array using splice() which somehow made the problem worse and I tried skipping over an email that's already been sent using continue; statements but that resulted in running even more times.

Any help would be greatly appreciated