SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'efb6f562e1b5583cf405c79661f380c3530d44afe07c72018513761acee1cd71' 
  AND token = 'MrHgsQypSx9cOFh0nczPsTM/8pYmIJbCvG1hMsQL5Dk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00048

JSON explain

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