SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c4df586841f47a43d9cd126a029e96cf5b5fc3682dfff2a38f0531bf8e06216c' 
  AND token = '74ZlGoWdNILn7iLy0UWUxckh2gHgxEPa9nPXJQBU3K4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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