SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5a9323e97e79ed32abc047eb3ad83baf058d75efe1ffb45604187067f6de5b8d' 
  AND token = 'Bz4OO0Zj+YmEHfH9MF/lYvgUtZN81R8I6+K7O/5DkuI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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