SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '17942ec23df2aad859ceedda6f2a11f456e24e36f4ad5fd497b2a3abf18b794d' 
  AND token = 'PkEr+WdTvR3pNWBCzyHsPrpl7dzObG8kF4FdFtDMeh0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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