SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5b64da2eac0975fda123028f7a445d13c8407bd5b5ac820f62678d4cd38354a6' 
  AND token = 'HYIyAgjJFZCY0+kYnKOqLZCMMsbT4PlnuejMJN/eo6Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}