SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'e19a6d8d4a95c37e6c49f5c673f382a4e95264b593883cd1223fb9d806ae9f36' 
  AND token = 'UDhzWpO3gA1PJx0X2q2EE8DIuaDqxnsV1btdIWOvq1Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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