SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9f57c362d79a801668e877b205dd179a30662fc030e02b5d2ecbe9841fa96d23' 
  AND token = 'lj5ElMBS1qZtcQW9L4wQEbx6npgdQFbOGc7dxRb1CkA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}