SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '31ec0a3f12a2f23bfe90405a897ec07ff5be54ce822bdabc9a36150108988134' 
  AND token = 'PTwLpUuemHvu2C/GOHTeHEB6WjKDp51DYggNV+hNpWU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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