SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '34bc7c213a7cf07e472fa3d259238aae5c5b1fd3ac95a6ee4f91768e84e5551f' 
  AND token = '846GMmX2JVWMwFv0pDmkO2O5E/DBYaEDlJLFKZplxoY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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