SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '393de589493c52ee12ad31ae8a66c23fadf3d14585c34bbf55c094ffdaa94c04' 
  AND token = 'XmwRPS6Nu/xdGFLfKiMMW1WCblb8mygfeeYzva0Ww4U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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