SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8d0159898e0f9b95dfb6dcb6cf86533ca4ec7b72603de262de5f415a8e6ca262' 
  AND token = '5+ZJt6VWUwc1DA2mPv7LB/8q2+34BgBdNXlD7gB2IzY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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