SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ec0cc55e37a57740af9f276411925a2b1a9f680927cdd4d8821680d8b8f075dd' 
  AND token = 'xvj+wusWX11lKRTpLhDwJa4ZfqDU/0Hv+7pbdu9ZDZs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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