SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '811373ceb59c8c76e45f61cb5aff22c922d0b4d0822853ccb32a68c316315520' 
  AND token = '2IWh5wvXw7TVc+WUGntYxPIFsGcIw8g4VgpsaIsa9V0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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