SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e328c1e5ddb4b5f8dafc8b9398ba67aebaeb3db5dfcd5e4e17e7e8c1e864b2e5' 
  AND token = 'AWDdoe35P+NDVIfOszHWYKBwOFFl2whXq0GgW6SXwn8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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