SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '78845d44bc65ec21a83ab2f9057c24b1c087fc7d3ff20a53d973ed477cb040fc' 
  AND token = 'DmOKUmlfmW4pDhWbUg/zMgG9znKGWZ0enmtferlB/Yg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}