SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f85adef36eb233979ae713992c27b54bec2569669b9af278fb0aa988cc6a545d' 
  AND token = 'k7HUZby1oYvP/CjsqyI3vp0rOwTqBVjhDj56oeS12J0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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