SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1cadc51de6c166af7800f6169a66c539db84eae06bad9d7a6dbaffcfd09bb7c7' 
  AND token = '8E/EEPjC5nwwsJpH9kpHZ8atlWZ+i1U7sbLXEdB4lDc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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