SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '98f56bbd0356c839f163eddaabe09328f49d75fddf4155988fcee8748b2e845c' 
  AND token = 'RszyhsM+839DFpn782vv/xSr+0Im9Vkgux0TOpU8vyA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00054

JSON explain

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