SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5329d31c65da4ccb0152008533bb8da7871d4ce05c8cb0618be33c708e3df92a' 
  AND token = 'I3xPcFJUJHS8UnT2FIT5cWMGzory0O/dkDsST/yRhHM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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