SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ba817a3293359c6eead066948c10ed51b3b798103b65c8fd861b1afd36c27ad0' 
  AND token = '8r3vNsRarJauvBeKOLkBEB+wVUpGgoJM1GG/5AjGcIQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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