SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9a3c740a7667559e5b9c995cb8db96b6740fdb7de783e53fe1859cd1cfe0c6da' 
  AND token = '/VIA6uYD27RqKe//jji2H3FrtCsjPFCg1Whqru4IgoM=' 
  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"
    }
  }
}