SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '69a9d59630d08902ae692bbd8d380d876d93eee8aa34eba1d35671f0b00e5c06' 
  AND token = 'JMLCEFpf7ngjK203Y3/rt35FRLTQyTYI0aUy/ChavLI=' 
  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"
    }
  }
}