SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '61c216e0bbf48f380f0df4621e9305199fea479e3f693d2ed6d8f760b96d9e61' 
  AND token = 'd7QRBJIPhw5iJaezk1nlcLC7yGxbzpRkUb4sRz6ACTA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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