SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '427a692d48d4bc8890d89e32f8e54e739c874941622f64667a6995c87385275d' 
  AND token = 'sXoEXzyy5Em589uACOryg5NfQGA91xgpCbz5PQo7wFE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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