SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '057466cd495a0b27a8fd8cc2eb9e0225dd385301283c06e6cf7df5d7c93c09a4' 
  AND token = '6YdQlOj3BOQ5cJ4lq5+9DWYFvOpnvbhoTk8jgh7TkPI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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