SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e8cbfca7841ec09279575de13d78782727094abeb61a04261efd2776136a8625' 
  AND token = 'OsYHOHBDaPbXYGniN1843LBTRW8tJbHArQ8rFpweGlg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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