SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '750ab45368804f87c517624cc789fb3964c89539d1f12f864d1fc8f2223ee2d5' 
  AND token = 'j6urJR3thKl2eXxmhPI3wmb/yvVe17yH9eX4IGEJfJQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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