SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7ac9f1809cedea71f1670e1488b6ba8d35bdae389598417279858712b95a3f53' 
  AND token = 'up/d9inxGqtFQAoVsqSXSdmzzFMgShTuZt6lCW4RFjQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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