SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6eaf2624cc4ddf88e8e1bbe2db1ee4ac36ac8324d418527f442aaed1f612873d' 
  AND token = 'ogUB+jufvitN94duFxqEWkIAzWMbSRYUkY1kzeqK7PI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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