SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2fbaf549c417f26baafb444a4be2818f78d66cbde8d906a6096b78c56b245920' 
  AND token = '8HqJDT+Ix2mdjTML0e4TfDbidN+AVs7GxUyzLvyf+iA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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