SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fe433d9247ce720697bb67595b4bea32bf994ef8887afd11f607d67c1c30d688' 
  AND token = 'Pi4hFg395KSA6xSn//0VHytnkMcpqlRwn2jvvWIF0lo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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