SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a72ad4a754b6233bde1168282b5b9cd5402ed5b2276d112110cd5994ae6f9483' 
  AND token = 'vnCI4qTcygr/N/57/mOSDEUehukWhqjoAsrygTPAiRY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00058

JSON explain

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