What Rigveda verse 8:64:1 to 8:64:4 states? Does it say to kill the infidels?

I do not know from where people get the concept of infidels being persecuted or killed. We simply have no concept of that. Vēdas lays down no injunction of killing anyone based on their beliefs.

The only people asked to be destroyed as Dasyus, Vṛtra, Paṇi, Vala, Asuras, Yātudhānas, etc… who are equivalent to demons and ogres or are considered psychological enemies who prevent us from realising the truth.

Now let us look at the verses and their meanings:

उत्त्वा᳚ मन्दन्तु॒ स्तोमाः᳚ कृणु॒ष्व राधो᳚ अद्रिवः । अव॑ ब्रह्म॒द्विषो᳚ जहि ॥ ८.०६४.०१

May the affirming lauds render you rapturous. O thunderer, perform achievements. Kill the enemies of the world (or) Vēdas.

Here Sāyaṇācārya says that Brahmadvisaḥ should be taken as haters of Brāhmaṇa (ब्रह्मद्वेष्टॄन् अव जहि). Again if this is also taken, there is no mention of the killing of so-called infidels. Brāhmaṇa haters can be also Kṣatriyas like Kārtavīrya and others. So if one adheres to Sāyaṇācārya will also not get the meaning of infidels being killed.
Brahma has the meaning of a Mantra or the essence of the Vēdas. The Amarakōśa (Trtīyaḥ Kāṇḍam, Nānārtha Varga) also states this. Hence Brahmadvisaḥ can also be taken as those who hate the Vēdas or are against its essence.

प॒दा प॒णीँर᳚रा॒धसो॒ नि बा᳚धस्व म॒हाँ अ॑सि । न॒हि त्वा॒ कश्च॒न प्रति॑ ॥ ८.०६४.०२

Crush with your feet the evil Paṇis who have no achievements. You are great; there is none like you.

Sāyaṇācārya here says Paṇis are Asuras who traffick and steal wealth. Here we can take wealth as literal wealth or in the case of spiritual interpretation the wealth is our knowledge. Here even I agree with Sāyaṇācārya. Paṇa means wealth (or) money, and Paṇis are those who steal it. Again there are no infidels mentioned here. Unless people are dumb enough to take Asuras as infidels.

त्वमी᳚शिषे सु॒ताना॒मिन्द्र॒ त्वमसु॑तानाम् । त्वं राजा॒ जना᳚नाम् ॥ ८.०६४.०३

You are the lord of those who press out the Sōma, and of those who do not press the Sōma, You are the lord of all people.

Here Indra can be taken as Śakra or as Rudra himself (Dēvanāmhṛdayēbhyō Namaḥ KYVS 4.5.9 and Atharvaśirōpaniṣad). Here also no mention of infidels. Rather here the Lord is called the ruler or King (as per Sāyaṇācārya) of all the people irrespective of them being Āstikas or Nāstikas. One’s personal belief does not change the fact that he is their Lord in the end.

एहि॒ प्रेहि॒ क्षयो᳚ दि॒व्या॒३॒॑घोष᳚ञ्चर्षणी॒नाम् । ओभे पृ॑णासि॒ रोद॑सी ॥ ८.०६४.०४

Come here to your abode, come sounding from Svarga for the sake of strivers. You fill both the Svarga and the earth.

Here we ask the Lord to heed our call and give us bliss. Both Dyāvāpṛthivī is filled with bliss only because of his grace.
As per Sāyaṇācārya, Indra is called to the Yajña and then in turn showers rain and created lightning. His meaning is very low and makes the entire verse look in very inferior manner. But again here also there is no mention of infidels at all.

So whoever makes such a claim is literally a man who has no knowledge of the Vēdāṅgas. Neither Wilson nor Griffith renders them as infidels, so this interpretation is pure propaganda.

Hope this helps.