JSFiddle - React, Tailwind, and code Playground

HTML

<select class="check-in__select js-check-in-times" id="time" name="AptTime" required="" aria-required="true" aria-label="times filter">
  <option value="2021-07-28T08:15:00.000-04:00" data-group="2021-07-28" style="display: none;">08:15 AM</option>
  <option value="2021-07-28T08:30:00.000-04:00" data-group="2021-07-28" style="display: none;">08:30 AM</option>
  <option value="2021-07-28T08:45:00.000-04:00" data-group="2021-07-28" style="">08:45 AM</option>
</select>

<div id="date" style="font-size: 24px; color: red; font-family: sans-serif;"></div>

JavaScript

var date = $("#date");


// Show the date only if there are open spots
if ($('.js-check-in-times option:visible').length === 0) {
  date.html('');  
} else {
  date.html('Working now.');
}