SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3f7edf772bc17cf99019f4e2fbf32583646294d0e31be9d8a49ecd7836e814d3' 
  AND token = 'owUzsXckWa6vs1HeCHuNeXS8waF4uXu2Zfk74MJj5HU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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