SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c8aaf157f49fe049476a897b9411fff33b9510282159371ad40df177fcda646a' 
  AND token = 'YTKVffTI7pmhhI3uoRnjwOqvJV0iNBi89OV4W1sTFPI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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