SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '51099a70f7ce3b22e490d8827833ed0426ef802e234335f21e0f024c7bd440a5' 
  AND token = 'DugJFZWPIYw8fc1Eb/ln7MHVa48b0Wg97Wbpdcf8tlM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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