SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '320042bddb9c2af63a8a96bb11f2f12750f503912f25a8979b40348a0ab4ab38' 
  AND token = 'O7rSGVC/2bAsh9GTJYmnu0tVS5z4jV+fgKVBO8QrT04=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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