SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8acbbaae767aa634ce8f7402495a7980da3ea936cdc8590334e6f9641bf36fae' 
  AND token = '5AyQkWm1ruAlRctBXtOLqg1IbGEgLTpMCjpwWeDCs2s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00013

JSON explain

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