SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '76dc469275eae3ed9d81aa4eb8ae86ede30c68ffb1c4bcc6426f1fc95f7a4511' 
  AND token = 'sbxc5s7ADAlyx2zsmeBnTIRcDQLAuZIl9a0tGBwWIMc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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