SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '5c548750443fa774dedf9bd778402a3a3a63017d276a88dea63f340595af2412' 
  AND token = 'lZyh8UfhOP7WUDzGD0zD7QXx+eWkw43jTDaVhy0ywPU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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