SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '8e0e20e3f5be6c4eef6f8ce1f8b7e77bb4f2d41e1d5790f118cc3cf0a3b10a28' 
  AND token = 'nUUjwJqZZkTueFkuAMxWUWAjlpk35MvXMGI0XszPGJU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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