SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '14b45f1e5b1f841629c35ebabb34d6838f5687df21055e99add76d99c1ce7c02' 
  AND token = 'xYGV+nNN+Pp6aNnAPpBXrArjsSOSS9VXmlQ3BtSKYxc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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