SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '3d21fe9efa129cf3e50d9b60a9fb4c031f959a344b04598f0ff2563196ea34ee' 
  AND token = 'FckgQKj0dIPhAqN1pZrpUWqTgEEEJaLZUL3EzfRGVGA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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