SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '49bc855735da1fb04e46145e65eeab20742d36627bebcfc4dc8228535b8dd280' 
  AND token = 'tnbGwwuNs5C+Qbjg5rltynbFWEopcNnYICECHA9zqJA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}