SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '940bdedd70a0b75b3e76832547235acb8f5d26962ae0d8a048f35f8a639cf010' 
  AND token = 'B1BMT14451+TaVnXJYP4W+6qCGjEQYcaXZDrLMbyEBg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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