SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '59b3d721ac8e73357a501db92a2e021fd1d498abe41b5f55ccc549345201fc83' 
  AND token = 'E6YVjL67pJnpQeikmSlBlcPkZTZDeu23dlfIReEFdOQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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