SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '27a988e637d050513a92fd63313fc5ac9f2e1a08ef86248ac5bf7c174643a4fa' 
  AND token = '1z5lsnvLaBfgZTK1wViW+c/gLWa3Pdyj+GPIdu7pvUo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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