SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd73ab7b01c2feb73c95b6d6f582c23d1bde2bbd2607d5475df9abe96f1e2b220' 
  AND token = 'YoCQkcqVBq924ZXUlslM4LZIvcZEnmnSvQRKxOcYyT8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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