SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3d228846c656bbeaf99560c66b799a5a4683674ed3d128898401f8b80d7a43d3' 
  AND token = '5YMI9TOlMt1w7Ofs6JBwa4LZl9RUKw7DnUW/VGJSPuI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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