SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7be16e94548c971bfb109fe102056a1efc0ad3844390c3d79c0d7e42f8983790' 
  AND token = 'Dy+DltPXVs4AHxxW0yfJspZozM0RwPvBLNuVgD3whas=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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