SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '79b3b215f43c8768615b140cb8128e793677b527797d461ea21702defb500ece' 
  AND token = '920ULYUXiyxPcBm4l8agFfoba5K+vN7SnoUDb7dNuns=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}