SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '678231fb74e7761933c3075a6f628dc8832eadcd1c7585f3978b00d25be0d25c' 
  AND token = '9ktOVm3E0keLwJBNHOSy1WL6zHjFWaBGwvL5gYS7Guk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}