SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a560e82d6d3a01a830f9e561fab89bf42d380d0ed909adca7788b7ad2ea82844' 
  AND token = 'YZLSdVWKp6EjQHhUDXllE+70ETzIX8swrMt8qAYsm10=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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