SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'da4f3545d817f2260365f5c8d99d55fd9c66a6cad0cb24cbcd7245598b603771' 
  AND token = 'YFxLrmJG1o/Dhu8cUY2QZgWzT5ziNVQEQrT1vEHWSeA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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