SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'b291a6e9c140f2bcb3a73b70f4c590df79ebe21b691925ed3f40248c60425a4f' 
  AND token = 'JrNuvorzSyYELP9doftiYeQh658Yzj9zliM9YK1HRkU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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