SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9461f74f874e126271532afcc8da78c2b6983593d5fd70359c49254ecfe5cbac' 
  AND token = 'nWwG9YVHUE1e41CSdgV6Ft5NbD72KQt0mA6x5sjyVlg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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