SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4317b467494f076d63e9d5f9ebb5a4b51bce378b5483124be91f637d5d1f333c' 
  AND token = 'KLeB78vJVRQzCzpWfL4sr7KQ94BILhlX++xuwDmQI+0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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