SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'a09a1541c29c257b4d6abd24c94a821624c8db4fab44cbd4a0f1e6dc58cfd103' 
  AND token = 'vvL/OgLPd5Rp9RvS5Sq5s506ikp+HKHNZhtMxKpGx2Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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