SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a767cd546f95a5db1e53ee208eba3e43fa6dc66c282bc482bbd09182db25f359' 
  AND token = 'DOvPvUiwe6ITIp7emQlzaNFoIYApEcuDCtlSQ3CwIoE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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