SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd2aadfa2edccf4ea6d458f60345a5bf74efed0ae1012b3905ccf5fa4a24ea8dd' 
  AND token = '34zxXAQLxKrBsobpZnrERf1jkdm/PjUWkkFtlyre9ss=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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