SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '781851b138dd159479410c3c40a4a9fff8e642d3247ae7b1ae12b103a971d227' 
  AND token = 'LlBe73ZtVCI/WqUpaP/CiX9ShYTZGRjrC6hWs10LsUE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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