SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'dc98c00b4521db06f73e69978180fda1a98196748c5dd060fa587b538210d719' 
  AND token = '8fUKcMx6z/FPbnbbj5CiT6FTcQQbLXqW+XJyUnglMsg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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