SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9326648985d35090e1fdd978a31f1d641f9ce665db7fb52446ce4b78b3d88804' 
  AND token = '/3X3twu8DJuM/AX4mxSN03FfoTWXvLisbtfCLBODM70=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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