SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'fe0e7e6e3a7740f14a82159ff0f4b93a22dc135782d9a74988ef02adfe5e6987' 
  AND token = 'UaKCFPOetigbwEc6KXFw6DPig9zZfEMd6glA+c4/JXs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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