SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3bcd5a817d21607a5b96b551ee754fde1e1108cbd7acd8f393b07d599d10ef91' 
  AND token = 'CH8JhGwKx4KzoS/LXmh19ZoDWuCXsvbyQ2lTsjM/hDA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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