SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e49ce73cc372cc56e1169fb49dc6580262e14c7045079cfa53d840e7480c83ee' 
  AND token = 'Ao25y8ORXnpvjCHJt7BbqUh6UG2+bPJrljyiYj7d/Bg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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