SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'f5d95f4880dbdd350fe8dee3d6cc1e149b41adf12b3295d6256ced6e224c447c' 
  AND token = 'DXCxjvV8mn7WDXi65YkfWL1cras0UluLIWCrh7j4w0Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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