SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eb7b6c354331c2c2ae21da2059e0ceccf697e0ba0ad1037c27f6545a6628bbb0' 
  AND token = 'gHLWoLOeqNiP5xL9AECsZi9QcGr6f+fGz2AIVnJBM+g=' 
  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"
    }
  }
}