SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4e0c18f2ff2b7a45c7c9cdbbd16d5cb6c55750d84db5ba4f54237e6dc295fa77' 
  AND token = 'aYwf1ya+f0TUC3J0mo3Fe3FUimdvd5E3iUOktrhipDU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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