SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3b08b24e857704e9ba0cf897873dae52d56edf1349a5cb81039d39e41962ba22' 
  AND token = 'JLYatbYh1AhpDwV8XU/uS0WJXtHPewFnKHYuFDuAmpA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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