SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '20f579da4585b14b8ec77e27f654ede08df00e639f12cb61edc70180f82aab77' 
  AND token = '2TfQNxV/oa1rhqsZhIhgVbuwhUcEG+iZWPYiITAhLFU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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