SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3b4f0706f12401b3ee3b6a23bc58760cbab0c31f41bf3cb09a8fe6be6a65bdeb' 
  AND token = 'mWf3um9rhlxGbQdNzASPzMqK25upLfugPF7jL8FsisI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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