SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '608a8f3a4bb5d42fbdd9a98d23f677e16dfb7acc2cef5b653dd73792d8b7237c' 
  AND token = '0XPzGzsyKb9w85qoaqVB/CZwE2WMlz1VUgvrvTn5G+s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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