SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '76079472f1edeb4d2a09c6c59a78ecbc5f76ead8fccb7f7afef48d45cd394223' 
  AND token = 'aPLT7APvpl79WNtVfrPOW0dbUAtbrWus2OOxCp10IW8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00050

JSON explain

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