SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '8d388eddecf460e1f5450d13524df79fd24f52913b564496d3b113c24caa3e12' 
  AND token = '4Zp2TCzES1N07Mf2ThpIYZRT1VQ8dZU2do/peJGrMt8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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