SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '112aaac12797dd95e2e7e72c9173067e4eadab7f36995284a638db4271727639' 
  AND token = 'zg4rkwR787XrAASD1IWzMHIB56dZDhKFPQ3BOuXPHs8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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