SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fa6f95cb35611722a2ad644749d610fb45d79a95f8c51d118a2392010e715548' 
  AND token = 'NQ/UDIGqoKSSOEnD89FTa5XiHYZ/mNIaf7TQaZAZv80=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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