SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '42ba351e8d235b6426dcd5c9638f22ae9cc3ff0254b3120170f873f51e6d56f6' 
  AND token = '7R+efAqwX9kZ50nNHHFGZcYtIxYRuW/TJhzXi9fWY54=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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