Ключ-карта лежит в сейфе.

Лежит literally means is lying or lies. In this sentence, Russian uses a more specific verb than English often does.

So:

• Ключ-карта лежит в сейфе. = The key card is lying in the safe.

In natural English, we often just say is in the safe, but Russian commonly uses verbs like:

• лежать = to lie
• стоять = to stand
• висеть = to hang
• находиться = to be located

Because a key card is imagined as resting flat somewhere, лежит sounds natural.

Because this sentence describes location, not movement.

• в сейфе = in the safe → where it is
• в сейф = into the safe → where it is going

Russian uses different cases after в depending on meaning:

• в + prepositional case for location
• в + accusative case for direction/motion

So:

• Ключ-карта лежит в сейфе. = The key card is in the safe.
• Ключ-карту кладут в сейф. = They put the key card into the safe.

Сейфе is in the prepositional case.

The dictionary form is сейф. After в when it means in, the noun usually goes into the prepositional case:

• сейф → в сейфе

This is a very common pattern:

• в доме = in the house
• в офисе = in the office
• в сейфе = in the safe

Because the subject, ключ-карта, is:

• singular
• third person

The verb лежать is conjugated here as лежит, which is the 3rd person singular form.

Compare:

• я лежу = I am lying
• ты лежишь = you are lying
• он / она / оно лежит = he / she / it is lying
• они лежат = they are lying

Since ключ-карта is one thing, you use лежит.

Because it is a compound noun meaning key card.

In Russian, some compound nouns are written with a hyphen, especially when they combine two nouns of roughly equal importance. Ключ-карта is the standard spelling for key card / access card.

Other similar hyphenated compounds exist in Russian too.

Also note that the whole compound acts as one noun in the sentence.

Yes, ключ-карта is treated as feminine.

A useful rule with many hyphenated nouns is that grammatical gender is often determined by the main or final part. Here the second part is карта, which is feminine, so the whole noun is feminine.

That matters in other contexts, for example with adjectives:

• новая ключ-карта = a new key card

In this sentence, the verb лежит does not show gender in the present tense, so you do not see feminine agreement directly here.

Yes. That would also be correct.

• Ключ-карта лежит в сейфе. = The key card is lying in the safe.
• Ключ-карта находится в сейфе. = The key card is located in the safe.

The difference is mainly nuance:

• лежит is more concrete and physical
• находится is more neutral and formal

In everyday speech, лежит often sounds very natural for an object resting somewhere.

Yes, Russian word order is flexible.

The neutral order here is:

• Ключ-карта лежит в сейфе.

But you might also hear:

• В сейфе лежит ключ-карта.

That version puts more focus on where it is. English often needs intonation or extra wording for this, but Russian can do a lot with word order.

Both sentences are grammatical; the difference is mostly emphasis.

Russian does not have articles like a or the.

So Ключ-карта could mean:

• a key card
• the key card

The exact meaning depends on context.

In this sentence, if the meaning shown to the learner is The key card is in the safe, that comes from context, not from a word equivalent to the.

The stress is:

• ключ-кАрта
• лежИт
• в сейфЕ

Stress is very important in Russian because it is not always predictable and can affect pronunciation strongly.

A rough pronunciation guide:

• ключ-карта ≈ klyuch-KAR-ta
• лежит ≈ lee-ZHEET
• в сейфе ≈ f SYEY-fye or v SYEY-fye, depending on speech flow

Because of a common Russian pronunciation rule: a voiced consonant can become devoiced before a voiceless consonant.

Here, в comes before с in сейфе, and с is voiceless, so в is often pronounced closer to f:

• written: в сейфе
• pronounced roughly: ф сейфе

This is normal in spoken Russian and does not change the spelling.

Only if you mean on the safe, not in the safe.

• в сейфе = in the safe
• на сейфе = on the safe

Russian distinguishes clearly between inside and on top of, just like English does here.

So if the key card is inside the safe, в сейфе is the correct choice.

The dictionary forms are:

• ключ-карта = key card
• лежать = to lie, to be lying
• сейф = safe

In the sentence:

• ключ-карта is already in its basic form, nominative singular
• лежит is the conjugated verb form from лежать
• сейфе is the prepositional singular form of сейф

Seeing the dictionary forms helps you recognize the words when they appear in different endings and forms.