SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aadb6ea99c12cf643458eaffde6ff6d90ec9a02926cc74c8fd88fffd6d415a79' 
  AND token = 'dJFBQHJgy9giTw841DjTTZ8nJfFCbT+VAnojds7h8gg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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