SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cd8671a30656234298ac2991f2ac8dc534b077c3e7a8c334c5331932857779e3' 
  AND token = 'VE0DCGOFVbH9cpE/DAqm51qbxGHWqSzo8jjff5jhwXY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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