SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3b16ff7f4a7b8556b288cde5c64a7180d50bfb93211af70ab71298a258fb67f1' 
  AND token = 'Wn9mmLTgtnuWVUhQumsr+XZ8Rpzq7xWNP7TqyhFZ4Fg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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