SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4f1b047a50f424b8b480cc217d773ca2845396d157b005921dfa9d2bf28e56b2' 
  AND token = 'xaIk8nwsLYBRJhNU2Yw1Yw/gMRcDu5Z8Qiukr+LZZfw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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