SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '168e6bba52f62cf4842c9647b5c054f47049d3bd249a56ff46cac76a97ab1b92' 
  AND token = '7zqJm70dj8QamNs6826SuthFBqK9/l+FsK1cw2nI9jE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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