SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ae482796c54e3d917d1106247ce770477c120db5af93784add8e790d577e822b' 
  AND token = 'KitzJwhBSubTfMZZTvxPLMoBRqxKDe1xOZZbC9CzbGI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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