SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '03ad446a191a4003e5e6bdf88de80005bc5bb9f7348621d297cd226aa60fa574' 
  AND token = 'AZAXcGO0aMcFIJQoGgza9w0dewxIdmD5imGRUvVM2r0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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