SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'd671754cc2e47d9b29dcbde6634b47886f647855e54fc54eb71219dd35a6d08c' 
  AND token = 'TnO3Ug+pEQRTkGTSk/aaW0ZGpjaYeMT7yjP/5p9rsbU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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