SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd783734b5577c875ab7691ce38276fc6555267c7e8a13456faa5365ceecffc86' 
  AND token = 'q7XqGr0IQfeOmPqMI9zDrfTRo0UeDYO7nRDNAwl4uuQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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