SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4f62a020785911ebb6434727b89991d4eabdef701d118e6a442916553588243b' 
  AND token = 'xhf1o7fZqwDn0pi3nP+F4LlQOIt37OptRl32IeaYqjM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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