SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eb40637230b76dc17d194cb453d541be2ef6285d139e801631030c0374436d56' 
  AND token = 'GXiYC9MKTxIlZsbQnE5NmzdAU2nDdvQWl6uobZF29Q0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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