SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5887af13995a8e0211b92cdb29aaae39bf0c6864c35f71cdca06398088e90f7c' 
  AND token = '6Sc7JFFQE6E5MqMsxE1bDEM40vsW8pAoh4a8Hr4HOFk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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