SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '8c17399e21a90ead2abb016cd503496fd126452e3cf0d30824aa1e23c858414d' 
  AND token = '8RuSB0S5RpxR1XdnvTMzHVzTvbBwNB+H4hG/fD/A2K0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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