SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e50715fb808154c3767f4b5f543ed6a4ad911c3fe13caa3c38425e024d7aa602' 
  AND token = 'GsXs3CvV+OPaJVietH+rZtEeVcqoAawYbp1HFQNNYA8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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