SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8ee0c4caee1db492625b890fa01b16718d62008dbabedd0436637dae73a2f4d7' 
  AND token = '/J35MOWlBmCUgIEynyPHY3P0oyDR3BpRH1zy8KW2Nyc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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