SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a50241ccde73e59d670d452c188ecd3c51838652ccbc72115fa34ccd76820d58' 
  AND token = 'ZBpPhnkdhqRdFDaYaqhCxd4LHbmNbhqRGbUMrKwgS8g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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