SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '454f6a679e614cd0123c8e67b20b3b15cea0aa8b58b82b433c9af49986b43392' 
  AND token = 'oEmd0YM3YR6iHQV8n6pQCFGI+5gfNX8u5stUaDkppJI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00010

JSON explain

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