SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '83ad120cf09c703efdbaa65e7994f0b4313a2211a9275bc6236eae0549efb0ee' 
  AND token = '7ARHhgCA/zt6E4QcenuryBfNG713vJbu5KKnax/NAgM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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