SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3db920d5766ffc5fde7cfecaf5fb5d381969566503e4a6bc69a24b762c5fadca' 
  AND token = 'Y4zZgqRB3YRgYpLfCDq/1iFhtnAo0Nemln9uqDTzU6o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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