Translation:There is a laptop and a key in your bag, Sam.
Feel free to correct me—in colloquial usage, we often use “there is” even for multiple objects wherein each are completely unrelated to each other. Our sentence would best fit in that situation. We only use “there are” if there are multiple quantities of an object (e.g. “There are laptops and a key in your bag, Sam.”)
The use of “there is” likely stemmed as a simplification of the more verbose sentence of “There is a laptop and there is a key in your bag, Sam.” The subsequent term is omitted in conversations, thus leading back to our sentence.
That is my food for thought regarding descriptive language.