SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '03b5fda03a92383c186c3738533bf2cfa5ff23919991efb5cee84e530d8282d5' 
  AND token = 'RdMVXG2QR4Km+9xIHxvUcDMP8FnDSCLM+lHRTHAdPc8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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