SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3cd2db7d63116655fb8d41f1938c619720d648befaca7ebfacb5836b504c527d' 
  AND token = '18ZxHzf7yVMkYgmn4BmMP3UDfNWpGShwGGXmX12Vcyw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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