SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '41a9e26cfe8cb2af4e27ff000d4fee47e0dbfedd513fbcfd6ab4268245f5573b' 
  AND token = '0pDVBcAR61LJJHjflb/nkMRwBIjAvXG3MsevgqZEzFI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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