One should be aware during Salat

The Quran describes that the believers are reverent during their Salat.

[23:2] who are reverent during their Contact Prayers (Salat).

الَّذِينَ هُمْ فِي صَلَاتِهِمْ خَاشِعُونَ

The Quran says that the hypocrites observed the Salat lazily both in coming to the Salat (9:54) and standing for the Salat (4:142).

[9:54] What prevented the acceptance of their spending is that they disbelieved in GOD and His messenger, and when they observed the Contact Prayers (Salat), they observed them lazily, and when they gave to charity, they did so grudgingly.

وَمَا مَنَعَهُمْ أَنْ تُقْبَلَ مِنْهُمْ نَفَقَاتُهُمْ إِلَّا أَنَّهُمْ كَفَرُوا بِاللَّهِ وَبِرَسُولِهِ وَلَا يَأْتُونَ الصَّلَاةَ إِلَّا وَهُمْ كُسَالَىٰ وَلَا يُنْفِقُونَ إِلَّا وَهُمْ كَارِهُونَ

[4:142] The hypocrites think that they are deceiving GOD, but He is the One who leads them on. When they get up for the Contact Prayer (Salat), they get up lazily. That is because they only show off in front of the people, and rarely do they think of GOD.

إِنَّ الْمُنَافِقِينَ يُخَادِعُونَ اللَّهَ وَهُوَ خَادِعُهُمْ وَإِذَا قَامُوا إِلَى الصَّلَاةِ قَامُوا كُسَالَىٰ يُرَاءُونَ النَّاسَ وَلَا يَذْكُرُونَ اللَّهَ إِلَّا قَلِيلًا

The following verse informs us that one needs to not be intoxicated when performing Salat so that the person is aware of what they are saying.

[4:43] O you who believe, do not observe the Contact Prayers (Salat) while intoxicated, so that you know what you are saying. Nor after sexual orgasm without bathing, unless you are on the road, traveling; if you are ill or traveling, or you had urinary or fecal-related excretion (such as gas), or contacted the women (sexually), and you cannot find water, you shall observe Tayammum (dry ablution) by touching clean dry soil, then wiping your faces and hands therewith. GOD is Pardoner, Forgiver.

يَاأَيُّهَا الَّذِينَ آمَنُوا لَا تَقْرَبُوا الصَّلَاةَ وَأَنْتُمْ سُكَارَىٰ حَتَّىٰ تَعْلَمُوا مَا تَقُولُونَ وَلَا جُنُبًا إِلَّا عَابِرِي سَبِيلٍ حَتَّىٰ تَغْتَسِلُوا وَإِنْ كُنْتُمْ مَرْضَىٰ أَوْ عَلَىٰ سَفَرٍ أَوْ جَاءَ أَحَدٌ مِنْكُمْ مِنَ الْغَائِطِ أَوْ لَامَسْتُمُ النِّسَاءَ فَلَمْ تَجِدُوا مَاءً فَتَيَمَّمُوا صَعِيدًا طَيِّبًا فَامْسَحُوا بِوُجُوهِكُمْ وَأَيْدِيكُمْ إِنَّ اللَّهَ كَانَ عَفُوًّا غَفُورًا

It is worth noting that the word used for intoxicated ( سُكَارَىٰ / sukara) is not limited to just drunkness. The Quran also describes people who are intoxicated by lust (15:72), shock (15:15, 22:2), or sleep (50:19) as well. So this informs us that one’s mind should be focused when they are performing their Salat.