SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd0858303fd96945c17ea80ee7abb7f8651097bcef8480f4a50ed18dbe6efddbe' 
  AND token = 'vox9gqhdbf0FrsjQkGOaZtzxaUwSCiPuPjVIpc5JrXs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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