SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9b33b3cb4cbd14be2be51e3535a814f501ec57d2b0008a5d779b0279761b9ef4' 
  AND token = 'TUYEZBQfUhwFk6OCeGE2zyCtTfq/a9hRd3vnI+wsLN0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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