SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8306ed10cef4b6a40f75c8c15c624810a8e8f05a24a95d9c9111a53ed32cc40d' 
  AND token = 'VHmiGwDRAW3JpCBLptwGzvl+6CIuk33diivDHW/vie0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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