SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '74a42c1602c1c5fc16d14ccedc721531555738b094b1cf3206587d708c120b7f' 
  AND token = '/+GsZKagDPnBaREEftsNz0X/92ZyOG3W58+usRjLFSw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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