SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f3bf47363fc7ee96b9aeb82606d342347c3fbbbc9abe90242a314f45f7676fa0' 
  AND token = 'gFguCn6jlJVJcGvxQVvszyK8lMVx4Pm/MpAQoN/tjF0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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