SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '971481238aba7e11674dce74c2b9d6a594b8fd4e140a94ca000d807a29230dfc' 
  AND token = 'hqKicrbgYAfwSkhatQgm4/WhcVCdyVafIWbSWTO4mgQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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