SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '597dc2c78da98290668ffff5bd9a2c5b1c9deed4eda8da83016969931aee8186' 
  AND token = 'bRYekdkLTwd0HOFCwCE9Wlg11QdKG1AN/boOEoPvviU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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