SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '21d8b0664fc9ef1e8f965ddf9c8a85c5eeb0c77a5b822af98a9d250c0ff64c19' 
  AND token = 'oi4MNYfXolGSPiV6n5OgW7hAvTrO0u70CSkeFf9K0LM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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